¶1I write separately to underscore that the trial court’s ruling was an abuse of discretion not only in its failure to give due weight to the importance of continuity and stability in custody arrangements but in its assumption that there is a negative relation between a woman’s *542lack of wealth or her need or desire to work and the quality of her parenting. As this case so aptly demonstrates, outmoded notions such as these result in harsh judgments which unfairly penalize working mothers.
¶2The trial court’s primary reason for awarding custody to William was that Ana worked and had to place her child in day care, while William could afford to have his new wife quit her job and stay home. The court’s other reason was William’s larger income. No other facts appear in the record to justify the court’s ruling. Today’s decision ought to make it crystal clear that neither of these reasons is a proper basis for an award of custody.
¶3Read in light of the record, the court’s findings amount to “outmoded notions of a woman’s rule being near hearth and home.” (Gulyas v. Gulyas (1977) 75 Mich.App. 138 [254 N.W.2d 818, 823] (dis. opn. of Riley, J.).) In an era where over 50 percent of mothers
¶4The court’s reliance on the father’s greater income was equally inappropriate. The child’s best interests—especially when the child is very young— cannot be assessed in such materialistic terms. “[T]here is no basis for assuming a correlation between wealth and good parenting or wealth and happiness.” (Klaff, The Tender Years Doctrine: A Defense (1982) 70 Cal.L.Rev. 335, 350; see Dempsey v. Dempsey (1980) 96 Mich.App. 276 [292 N.W.2d 549, 554, mod. 409 Mich. 495 [296 N.W.2d 813].) In fact, common experience suggests that there is no such correlation.
¶5Stability, continuity, and a loving relationship are the most important criteria for determining the best interests of the child. (Maj. opn., ante, at pp. 538, 541.) Implicit in this premise is the recognition that existing emotional bonds between parent and child are the first consideration in any best-interests determination.
¶6This court acknowledged that fact when it recently held that a parent’s physical handicaps were irrelevant to “the heart of the parent-child rela*543tionship[] ... the ethical, emotional, and intellectual guidance the parent gives to the child throughout his formative years, and often beyond.” (In re Marriage of Carney (1979) 24 Cal.3d 725, 739 [157 Cal.Rptr. 383, 598 P.2d 36, 3 A.L.R.4th 1028].) A custody determination must be based on a true assessment of these emotional bonds. It must reflect a factual determination of how best to provide continuity of attention, nurturing, and care. It cannot be based on a presumption that a working mother does not or cannot provide such care.
¶7When the record contains no evidence as to which parent does provide this care, clearly the “working mother” factor operates as a negative presumption. Even more clearly, this factor operates unfairly when the record indicates that the mother has in fact been the primary caregiver. The use of such a presumption as a basis for a custody award is of dubious constitutionality.
¶8Furthermore, the presumption is inappropriate because the relationship between maternal employment and the “presumed facts” about the child’s best interests is not supported by reason or experience. Typically, it is the mother who provides most day-to-day care, whether or not she works outside the home. (Neely, The Primary Caretaker Parent Rule: Child Custody and the Dynamics of Greed (1984) 3 Yale L. & Policy Rev. 168, 172; cf. Klaff, op. cit. supra, 70 Cal.L.Rev. at p. 344, fn. 56.) A presumption which ignores this fact is likely to lead to erroneous and unfair decisions.
¶9Moreover, there is no accepted body of expert opinion that maternal employment per se has a detrimental effect on a child. On the contrary, one recent study on maternal employment and child development has concluded that “[mjaternal employment status had no negative relation to children’s development over a 5-year period. . . . Public policy needs to move in the direction of more flexible work arrangements for mothers, towards enhancing the quality of the environment provided for children, towards enhancing the personal satisfaction of careers for women, and towards promoting the view that maternal employment has no negative influence on children’s development.” (Gottfried et al., op. cit. supra.) Thus, the trial court’s presumption lacks any expert support.
¶10*544The burden of the trial court’s reasoning would certainly fall most heavily on women. In those cases where the father contests custody,
¶11Yet, under the trial court’s rationale, it is the mother—and not the father— who would be penalized for working out of the home. She and she alone would be placed in this Catch-22 situation. If she did not work, she could not possibly hope to compete with the father in providing material advantages for the child. She would risk losing custody to a father who could provide a larger home, a better neighborhood, or other material goods and benefits.
¶12*545If she did work, she would face the prejudicial view that a working mother is by definition inadequate, dissatisfied with her role, or more concerned with her own needs than with those of her child. This view rests on outmoded notions of a woman’s role in our society. Again, this presumption is seldom, if ever, applied even-handedly to fathers.
¶13The double standard appears again when, as here, the father is permitted to rely on the care which someone else will give to the child. It is not *546uncommon for courts to award custody to a father when care will actually be provided by a relative, second wife, or even a babysitter. (See, e.g., In re Marriage of Welbes (Iowa 1982) 327 N.W.2d 756, and dis. opn. of McCormick, J., id., at p. 759; Bruner v. Bruner (1982) 212 Neb. 473 [323 N.W.2d 104]; Atkinson, op. cit. supra, 18 Fam.L.Q. at p. 35.) However, the implicit assumption that such care is the equivalent of that which a nonworking mother would provide “comes dangerously close to implying that mothers are fungible—that one woman will do just as well as another in rearing any particular children.” (Polikoff, op. cit. supra, 7 Women’s Rights L. Rep. at p. 241; see also Klaff, op. cit. supra, 70 Cal.L.Rev. at p. 348, fn. 72.) This is scarcely consistent with any enlightened ideas of childrearing.
¶14The reasons on which this trial court relied are discriminatory. They fall unequally on women and men. They penalize women for failing to conform to a 19th century role which is no longer possible or desirable for many. They imply that a woman who leaves her “proper sphere” to participate fully in modem life cannot be an adequate mother. Such a view denies full humanity to women. It cannot be tolerated in our courts.
¶15To force women into the marketplace and then to penalize them for working would be cruel. It is time this outmoded practice was banished from our jurisprudence.
¶16Gottfried et al., Maternal Employment and Young Children’s Development: A Longitudinal Investigation, paper presented at the Annual Meeting of the American Psychological Association (Aug. 1985); Atkinson, Criteria for Deciding Child Custody in the Trial and Appellate Courts (1984) 18 Fam.L.Q. 1, 15.
¶17Steinman, Joint Custody: What We Know, What We Have Yet to Learn, and the Judicial and Legislative Implications (1984) 16 U.C.Davis L.Rev. 739, 740.
¶18Compare Jarrett v. Jarrett (1979) 78 Ill.2d 337 [400 N.E.2d 421], certiorari denied (1980) 449 U.S. 927 [66 L.Ed.2d 155, 101 S.Ct. 329]. Dissenting from denial of certiorari, Justices Brennan and Marshall severely criticized an award of custody to the father based on what was in effect a conclusive presumption that the mother’s cohabitation with a man to whom she was not married rendered her unfit. Such a presumption, the justices pointed out, violated the teaching of Stanley v. Illinois (1972) 405 U.S. 645 [31 L.Ed.2d 551, 92 S.Ct. 1208] that parental fitness must be determined on the facts of each case and not by application of conclusive presumptions. (449 U.S., at pp. 929-930 [66 L.Ed.2d at pp. 156-157].)
¶19Though custody is awarded to mothers in 90 percent of the divorces with minor children, this appears to be due to the fact that fathers seldom request custody. (Polikoff, Why are Mothers Losing: A Brief Analysis of Criteria Used in Child Custody Determinations (1982) 7 Women’s Rights L. Rep. 235, 236; Klaff, op. cit. supra, 70 Cal.L.Rev. at p. 335, fn. 3; Lemon, Joint Custody as a Statutory Presumption: California’s New Civil Code Sections 4600 and 4600.5 (1981) 11 Golden Gate L.Rev. 485, 486, 529.) In the 15 to 20 percent of cases where fathers request custody, they are successful roughly half the time. (Polikoff, op. cit. supra, at p. 236; Atkinson, op. cit. supra, 18 Fam.L.Q. 1, 10-11.)
¶20For example, in Porter v. Porter (N.D. 1979) 274 N.W.2d 235, the reviewing court affirmed a custody award to a working father because “he is in a position to lend more stability and guidance to nurturing the development of the children during those periods of time in which he would not be actually pursuing his employment . . . .” (Id., at p. 241.) As the wife had forsaken a career during marriage to care for the children, the husband’s earning capacity was substantially greater than hers. It was this greater earning capacity which apparently was the source of his “stability and guidance.” (Id., at pp. 241-242.)
¶21Conversely, in Dempsey v. Dempsey, supra, 292 N.W.2d 549, the reviewing court emphatically reversed a trial court’s custody award to a father which had been based on his superior earnings. The mother had cared full time for three small children, one of whom was epileptic and required special care. She had also done all the housework, chauffeuring, and parent-teacher activities during the marriage. As a result, her earning ability was low. She had sought a divorce on the ground that the father did not spend any of his leisure time with the family. The trial court nonetheless awarded the father most of the joint property as well as custody of the children. It suggested that in light of the father’s uncertain child care arrangements the mother could provide day care as a form of in-kind child support. (Id., at pp. 550-551.)
¶22Reversing, the reviewing court held that “it can be argued that economic circumstances never should be conclusively determinative. The reason is plain. In most cases the mother *545will be disadvantaged, although with changing life patterns this is not always so. It is not merely a question of prejudicial effect upon mothers; the danger in placing undue reliance on economic circumstances is its potential prejudicial effect upon the child’s best interests. The party with the more modest economic resources should not be excluded from equal consideration as the custodial parent. If the parties are substantially different as to economic circumstances, the court has ample power through its orders, if it be in the best interests of the child or children, to equalize those circumstances.” (Id., at p. 554.)
¶23For example, in In re Marriage of Levin (1980) 102 Cal.App.3d 981, 983, footnote 1 [162 Cal.Rptr. 757], the Court of Appeal dismissed the notion that the father’s performance as an “excellent custodial parent” was impaired by placing the child in nursery school at the minimum age of two years on a nearly full-time basis.
¶24See also In re Marriage of Estelle (Mo.App. 1979) 592 S.W.2d 277, in which the court affirmed a custody award to a working father, not remarried, as against an equally fit working mother. The reviewing court made no negative comments about the child’s placement in day care, but rather emphasized that the father often prepared the child’s breakfast and dinner and picked her up from the day care center himself. (Id., at p. 278.) It is difficult to imagine a mother’s performance of these chores even attracting notice, much less commendable comment.
¶25Other examples of the double standard include Gulyas v. Gulyas, supra,254 N.W.2d 818, which affirmed a trial court’s award to a father who worked a standard 40-hour week. The mother, a regional manager for H. & R. Block, worked 40 to 50 hours a week during tax season, but only 10 to 30 hours the rest of the year. She had greater flexibility in her work hours, she was at home when the child left for school and she picked the child up at a neighbor’s home one or two hours after school. (See Note, Family Law—Child Custody-Mother’s Career May Determine Custody Award to Father (1978) 24 Wayne L.Rev. 1159, 1165, fn. 44.) The father had recently undergone surgery for a brain tumor. (Gulyas, supra, 254 N.W.2d at p. 822 (dis. opn. of Riley, J.).)
¶26In its award to the father, the trial court “repeatedly emphasized [the mother’s] employment” (ibid.) and “noted that [the mother’s] ‘career and need for obtaining a better livelihood has diminished her manifested ability to care for the child other than in Day Care homes.’ ” (Ibid.) The trial court “did not remark upon [the father’s] inability personally to care for the child during his working hours.” (Ibid., italics added.) The court concluded that “the husband [was] more inclined towards the old fashioned virtues,” that “the mother of the child is an energetic and ambitious career woman . . . and that the father of the child is perhaps less ambitious than the mother, but is more of a homebody.” (Ibid.) These moralizing conclusions, supported only by the facts recited above, were sufficient to support an award of custody to the father. (Id., at pp. 822-823.)
¶27See also Masek v. Masek (1975) 89 S.D. 62 [228 N.W.2d 334], in which a mother who taught music part time lost custody to a father who worked full time. The trial court noted that the mother slept until 9 a.m. on Saturdays, failed to prepare breakfast for her husband who left for work at 7 a.m., and on occasion had run out of jam and cookies. (Id., at p. 338, dis. opn. of Wallman, J.) It concluded from these facts that she was unfit for custody because her “primary interests are in her musical career and outside of the house and family. ” (Id., at p. 337.)
¶28I concur in the reversal of the trial court order, but strongly disagree with the manner in which the majority reach that result—especially their tacit and far from candid overmling of In re Marriage of Carney (1979) 24 Cal.3d 725 [157 Cal.Rptr. 383, 598 P.2d 36, 3 A.L.R.4th 1028], and their denial of needed protection to an entire class of children solely because custody was not originally established by judicial decree.
¶29In Carney a unanimous court held that regardless of how custody was originally established, a child will not be removed from the custody of one parent and given to the other unless the noncustodial parent shows that material facts and circumstances occurring subsequently are of a kind to render a change essential or at least expedient for the welfare of the child. (Id., at pp. 730-731.) Put simply, the rule requires the proof of two ultimate facts: (1) a change in circumstances and (2) the present necessity for a change in custody.
¶30In its two requirements the changed-circumstances rule serves two distinct objectives: the finality of judgments and the best interests of the child—in particular, his well recognized right to stability and continuity. (Ibid.; Connolly v. Connolly (1963) 214 Cal.App.2d 433, 436 [29 Cal.Rptr. 616].) In *547the general common law the rule appears to have its historical roots in principles of res judicata. (Sharp, Modification of Agreement-Based Custody Decrees: Unitary or Dual Standard? (1982) 68 Va.L.Rev. 1263, 1264, fn. 9 [hereafter Sharp].) But in California it has for many years been understood to have as its primary and indeed controlling purpose the furtherance of the child’s best interests. (See Crater v. Crater (1902) 135 Cal. 633, 634-635 [67 P. 1049]; Carney, supra, at pp. 730-731; Washburn v. Washburn (1942) 49 Cal.App.2d 581, 587 [122 P.2d 96].)
¶31The majority’s reading of Carney as not extending the protection of the changed-circumstances rule to so-called “de facto” as well as “de jure” custody is sheer sophistry. In Carney we expressly held that the rule applied “regardless of how custody was originally decided upon . . . .” (24 Cal.3d at p. 731, fn. 4.) We imposed on the noncustodial mother the burden of proving that a substantial change in circumstances had occurred. (Id. at p. 731.) And we concluded that she had not carried her burden. (Id. at p. 740.) It is difficult for me to conceive how we could have established the point more clearly. While I welcome the majority’s generous quotations from the text of the Carney opinion, family law would have been better served if they had followed the principle declared therein.
¶32More troubling, the majority’s tacit overruling of Carney and its consequent limitation of the changed-circumstances rule to cases in which custody was originally established by judicial decree have untoward consequences and are unsound.
¶33First, the limited application of the changed-circumstances rule that the majority adopt is in conflict with the primary purpose of the rule. The child whose custody was established by means other than judicial decree has the same need for and right to stability and continuity—and accordingly the same entitlement to the protection the rule is intended to provide—as the child whose custody was established by judicial decree. Because it is not unreasonable to assume that the children of two-parent and relatively more affluent families are disproportionately represented in the class of children whose custody was originally established by judicial decree, the majority’s holding, I fear, will effectively deny needed protection disproportionately to children of single-parent and less affluent families.
¶34Second, most states—including, until today, California—appear to require “changed circumstances” to modify custody regardless of how custody was originally established. (See Sharp, supra, 68 Va.L.Rev. at pp. 1265, 1268-1271, and cases and other authorities cited.) The rationale for this position was explained in Carney, “regardless of how custody was originally decided upon, after the child has lived in one parent’s home for a significant period *548it surely remains ‘undesirable’ to uproot him from his ‘established mode of living,’ and a substantial change in his circumstances should ordinarily be required to justify that result.” (24 Cal.3d at p. 731, fn. 4; accord, Sharp, supra, at p. 1270.) That the cases—with the notable exception of Carney— involve a custody decree is plainly fortuitous: the fundamental question they all address is not whether to modify a decree but whether to change custody. No state, so far as I have ascertained, declines to apply the changed-circumstances rule when custody was not originally established by judicial decree. The majority, alone in the country, take that retrogressive step.
¶35The majority claim that the Carney rule is “unsound, unworkable, and potentially harmful.” Their argument in support, however, is hollow.
¶36Their first point is that the Carney rule “is unsound because, absent some prior determination of the child’s best interests as of some past date, the courts have no warrant to disregard facts bearing upon that issue merely because such facts do not constitute changed circumstances.” But if the Carney rule is unsound for this reason, so is their newly created rule: even in cases in which custody is established by judicial decree, such a determination is seldom made.
¶37In virtually all cases, it appears, the parents decide on custody in a negotiated settlement and thus do not dispute the question at a hearing. (See Sharp, supra, 68 Va.L.Rev. at pp. 1263-1264; accord, Mnookin & Kornhauser, Bargaining in the Shadow of the Law: The Case of Divorce (1979) 88 Yale L.J. 950, 951, fn. 3 [hereafter Mnookin & Kornhauser]; Kirshner, Child Custody Determination—A Better Way! (1978-1979) 17 J. Fam. L. 275, 286; Mnookin, Child-Custody Adjudication: Judicial Functions in the Face of Indeterminacy (1975) 39 Law & Contemp. Probs. 226, 232, fn. 22.) And in these cases “courts usually ‘rubber-stamp’ such agreements . . . .” (Sharp, supra, at p. 1279; see Mnookin & Kornhauser, supra, at p. 955, fn. 22; Kirshner, supra, at p. 286; Hansen, The Role and Rights of Children in Divorce Actions (1966) 6 J. Fam. L. 1, 2.) The percentage of cases in which a trial court initially determines custody in a contested manner is minuscule.
¶38But the fact remains that even when custody is not adjudicated and indeed even when it is not established by judicial decree, we may nevertheless presume that such custody is in the child’s best interest and as a result require the noncustodial parent to show that a material change of circumstances has subsequently occurred.
¶39Such a presumption is justified when custody is established by agreement. “First, most parents genuinely love their children, and it is reasonable to *549assume that the children’s welfare is a vital consideration in the parents’ decision to resolve their dispute by agreement. . . . Second, parents have a better informational base upon which to make a decision about custody. The adversarial process is an inadequate means to assemble sufficient ‘facts’ to resolve custodial disputes satisfactorily. Third, it is difficult to protect a child from the painful pull of divided loyalties when his parents fail to agree. Parental agreements help to preserve an atmosphere of at least superficial peace between parents and thereby facilitate a much easier and more meaningful future relationship between the child and the non-custodial parent.” (Sharp, supra, 68 Va.L.Rev. at p. 1280, fn. omitted.)
¶40Such a presumption is also justified when, as here, custody is established by default rather than by decision. First, as between the parent who undertakes to provide care and the parent who fails or refuses to do so, custody with the former must be deemed to serve the child’s best interests. Thus, it is altogether reasonable to require the latter to demonstrate changed circumstances should he subsequently attempt to obtain custody. Second, as Dr. Andrew Watson, psychiatrist and professor of law, has observed, stability is “practically the principal element in raising children” and “a child can handle almost anything better than he can handle instability.” (Proceedings of Special Com. on U. Marriage and Divorce Act, Nat. Conf. of Comrs. on U. State Laws 98, 101 (Dec. 15-16, 1968); accord, Bodenheimer, The Uniform Child Custody Jurisdiction Act: A Legislative Remedy for Children Caught in the Conflict of Laws (1969) 22 Vand.L.Rev. 1207, 1208-1209; see Watson, Psychiatry for Lawyers (1968) pp. 159,197; Sharp, supra, 68 Va.L.Rev. at pp. 1280-1281; see also Clark, Law of Domestic Relations (1968) § 11.5 at p. 326 [“if [a child] is continually being transferred from one parent to the other ... he may be a great deal worse off than if left with one parent, even though as an original proposition some better provision could have been made for him”].)
¶41The majority’s second point is that the Carney rule “is unworkable because, . . . absent such a prior determination the courts have no established basis on which they can assess the significance of any change.” But “Identification of a base line against which to measure a subsequent change of conditions is not as difficult as the [majority] suggest. The simple fact is that a demonstration of changed conditions does not normally require a preexisting record of all the facts that prevailed at the time [custody was originally established] .... [1Í] It is plausible therefore to suggest that the . . . concern about the necessity for a prior record is somewhat of a red herring.” (Sharp, supra, 68 Va.L.Rev. at pp. 1285, 1287.)
¶42The majority’s final point is that the Carney rule “is potentially harmful because it could compel the court to make an award inconsistent with the *550child’s best interest.” But the concern that application of the changed-circumstances rule in cases in which custody was not judicially established might leave a court helpless to intervene where there was no change in circumstances but the welfare of the child required a change in custody does not justify a limitation of the rule such as the majority have adopted. To begin with, the rule could theoretically leave the court helpless in any case in which it is applied—whether or not custody was originally established by judicial decree. The concern, therefore, is rooted not in the use of the rule in any particular class of cases but rather in a mechanical and formalistic use of the rule itself. In any event, “Nothing in the case law of the majority states, or in any of the literature in this area, suggests such a rigid application of the changed circumstances standard. . . . Clearly, courts can easily accommodate the ‘worst case’ hypothetical within existing law.” (Sharp, supra, 68 Va.L.Rev. at p. 1288, fn. omitted.)
¶43We ourselves have recognized that such an accommodation is possible. In Munson v. Munson (1946) 27 Cal.2d 659, 666 [166 P.2d 268], we stated: “This court has recognized [citation] that generally ‘until some change of circumstances arises which makes a modification of the former order of custody advisable from the point of view of the welfare of the child, the court will give effect to the former order and will refuse to make any modification of such order,’ but that there may be cases ‘in which, despite the fact that there was apparently no change of circumstances, nevertheless, the welfare of the child might require that the previous order of custody be changed’ . . . .”
¶44In any case in which it is used, the changed-circumstances rule, if applied mechanically, might serve to lock a child into a bad situation. To prevent such a result—the goal the majority strive for but miss—I would adopt, in the proper case, the following limited exception: when the noncustodial parent shows that custody has remained unchanged but inadequate since its inception, he need prove only that a change is essential or at least expedient for the welfare of the child in order to obtain custody. Such an exception is of course consistent with the primary purpose of the rule, furthering as it does the child’s best interests. It is also compatible with the flexible nature of the changed-circumstance rule. (See Foster v. Foster (1937) 8 Cal.2d 719, 728 [68 P.2d 719]; accord, Munson v. Munson, supra,27 Cal.2d at p. 666.)
¶45*551In sum, the Camey rule rightly protects all children against needless change in custody and against the threat of such change. Whatever harm a mechanical application of the rule poses in unusual circumstances—which are not present here—can readily be prevented by permitting a pragmatic exception. The rule therefore should not be discarded; it should simply be modified if and when the need arises.
¶46Lucas, J., concurred.
¶47More radical would be a modification of the rule itself—the removal of the first or “changed-circumstances” requirement. Such a modification would evidently be proper when the rule is applied to cases in which custody was not originally established by judicial decree: the first requirement, which reflects principles of res judicata and serves the finality of judgments, is strictly inapplicable to such cases. This modification, however, would also be proper even where custody was originally so established. In practice the first requirement *551has no independent effect and thus may be eliminated without adverse consequences. Where there is neither (1) change in circumstances . nor (2) present necessity to change custody for the child’s welfare, the renewal of litigation is as effectively deterred by the second requirement as by the first. Where, by contrast, there is no change in circumstances but change in custody is essential, under longstanding precedents the first requirement may simply be dispensed with. (See Munson v. Munson, supra,27 Cal.2d at pp. 666-667; Foster v. Foster, supra,8 Cal.2d at p. 728; Bogardus v. Bogardus (1929) 102 Cal.App. 503, 506 [283 P. 127].)