“The father and mother of a minor child have an equal responsibility to support that child in the manner suitable to the child’s circumstances. In effect, the state has imposed a sort of joint and several obligation on parents for the support of their minor children. [State of Florida ex rel. Dept. of Health & Rehabilitative Services v. Vernon, 138 Cal. App. 3d 827, 188 Cal. Rptr. 322 (1st Dist. 1982)] This obligation is not based on the existence of a valid marriage, but rather extends equally to every child and to every parent, regardless of the parents’ marital status. [Fam. Code, § 7602]”
“The obligation to support one’s minor child is further recognized in Fam. Code, § 4053, which requires that the courts, in implementing the uniform statewide guideline for support, must adhere to the principles that: (1) a parent’s first and primary obligation is to support his or her minor child according to the parent’s circumstances and station in life; and (2) both parents are mutually responsible for the support of their children. [Fam. Code, § 4053, subds. (a), (b)]”
“The duty to support one’s child arises prior to the child’s birth and ordinarily continues regardless of whether the parent has custody of the child, the parents’ marital status, or the fact that another has voluntarily supported the child. [County of Los Angeles v. Christopher W., 41 Cal. App. 5th 827, 254 Cal. Rptr. 3d 565 (2d Dist. 2019)] The burden of supporting a child should be borne by those who are directly responsible for the child’s existence. [County of Los Angeles v. Christopher W., 41 Cal. App. 5th 827, 254 Cal. Rptr. 3d 565 (2d Dist. 2019)]”
“Because the duty is mutual, a judgment of dissolution requiring one parent to provide child support does not abrogate the duty of the other parent to provide such support. An obligee-parent who nevertheless provides child support may be entitled, under a judgment of dissolution, to obtain reimbursement from the obligor-parent for the support provided. However, the judgment does not abrogate either parent’s basic duty to support the children in the manner suitable to their circumstances. [Carr v. Marshman, 147 Cal. App. 3d 1117, 195 Cal. Rptr. 603 (1st Dist. 1983)] Thus, where a custodial father abandoned the children and the state provided support, the state was entitled to reimbursement from the mother even though the judgment of dissolution ordered only the father to pay child support. [State of Florida ex rel. Dept. of Health & Rehabilitative Services v. Vernon, 138 Cal. App. 3d 827, 188 Cal. Rptr. 322 (1st Dist. 1982)]”
“The statute imposing on parents a mutual obligation to provide child support contains no provision indicating that the obligation is affected in any way by the nature of the parents’ custody arrangement. However, because it is presumed that a parent having primary physical responsibility for the children will contribute a significant portion of available resources for their support [Fam. Code, § 4053, subd. (i)], custody is one of the factors affecting the amount of support imposed under the statewide uniform guideline. For example, when the parent obligated to make support payments is also the parent with whom the child resides, the payments may be reduced or terminated during the period of such residency. [In re Marriage of Matthews, 101 Cal. App. 3d 811, 161 Cal. Rptr. 879 (1st Dist. 1980)] Similarly, the court has discretion to permit only partial enforcement of, or to quash in full, a writ of execution directed against a parent in arrearage who, during the period in question, had the sole physical custody of the child. Such action does not constitute an impermissible retroactive modification of a child support order. [Jackson v. Jackson, 51 Cal. App. 3d 363, 124 Cal. Rptr. 101 (2d Dist. 1975); In re Marriage of Okum, 195 Cal. App. 3d 176, 240 Cal. Rptr. 458 (2d Dist. 1987); In re Marriage of Trainotti, 212 Cal. App. 3d 1072, 261 Cal. Rptr. 36 (2d Dist. 1989)]”
[California Civil Practice Family Law Litigation [certain citations omitted]]