Mother was already pregnant with twins when they got back together. She asked him to be on the birth certificate so that the bio dad couldn't have any claims on them.

The bio dad has not ever even asked about them or their well being.

The man in question here, has helped raise them, in doing 90% of the care for the twins who are now six. The couple separated and she now is trying to threaten him with having to keep the kids 50% of the time and pay child support and they're not even really his children.

Can she do this???

  • 35
    Location? Family law can vary quite a bit between jurisdictions.
    – nick012000
    Commented Mar 16, 2023 at 22:13
  • 38
    What does the father want? If I were in his shoes I'd be fighting for access to my children whom I had helped to raise from birth, not fighting to abandon them, regardless of who the biological father was.
    – phoog
    Commented Mar 16, 2023 at 23:26
  • 3
    Yes, well I wonder if he could have the best of both worlds by reserving any possible rights to access, but not accepting the liability of betrayal by a woman whom he seems to have undertaken a fraud to help out. Commented Mar 17, 2023 at 1:10
  • 2
    Without knowing your state\country, it's not possible to give a definitive answer. The generic answer is that he was a primary care giver, so he's liable regardless of his blood relationship. If you live as the father then you pay as the father, even if you're not. Unless you live somewhere that the law specifically says different. Commented Mar 17, 2023 at 16:00
  • 1
    @phoog, most likely the issue is not about physical access to the children, but about financial arrangements. Child support laws can be draconian in many jurisdictions, including requiring the wage earner to maintain the mother and the children, but in the absence of that earner enjoying the consortium and family life, the shared resources of the household, the benefit of any labour performed by the other partner, and with the earner often already being liable for the costs of another new household arising from the separation.
    – Steve
    Commented Mar 18, 2023 at 12:30

6 Answers 6



For all purposes in British Columbia law, a child's parent is the person determined under Part 3 of the Family Law Act (see s. 23(b)).

Outside of the context of assisted reproduction, there are a series of presumptions that apply unless the contrary is proved. A "male person" is presumed to be a child's biological father in any of the following circumstances:

  • he was married to the child's birth mother on the day of the child's birth (s. 26(2)(a))
  • he was married to the child's birth mother and, within 300 days before the child's birth, the marriage was ended by his death, a divorce, or voiding (s. 26(2)(b))
  • he married the child's birth mother after the child's birth and acknowledges he is the father (s. 26(2)(c))
  • he was living with the child's birth mother in a marriage-like relationship within 300 days before, or on the day of, the child's birth (s. 26(2)(d))
  • he has acknowledged that he is the child's father by having signed a statement to register as the father on the birth certificate or agreement (s. 26(2)(e))
  • he has acknowledged that he is the child's father by having signed an agreement under section 20 of the Child Paternity and Support Act, R.S.B.C. 1979, c. 49 (s. 26(2)(f))

If by operation of the presumptions, more than one person may be presumed to be the biological father, then no presumption applies.

If parentage can be resolved by one of these presumptions (based on the facts in the hypothetical, it is possible that presumption s. 26(2)(d) might apply, and also likely s. 26(2)(e), since he is on the birth certificate), that answers the question, unless someone attempts to prove that the presumption is incorrect.

If someone wants to disprove the presumption, they can apply for an order declaring parentage. When hearing such an application, the judge will consider all relevant evidence, including testimony of parties and witnesses, physical evidence, genetic testing, expert opinion, etc. The burden is on the party seeking the order to displace the presumption, on a balance of probabilities.

Parenting arrangement

Parenting arrangements ("trying to threaten him with having to keep the kids 50% of the time") can not be imposed by one party on another. Parenting arrangements must be by agreement, or by court order (s. 40). If done by court order, the court "must consider the best interests of the child only" (s. 37).

Child support

If a person is a parent, they generally have a duty to provide child support for the child (s. 147).

Child support from stepparent

Even if the person demonstrates that they are not a parent, they can owe child support by court order if they are a stepparent ("a person who is a spouse of the child's parent and lived with the child's parent and the child during the child's life") who has contributed to the support of the child for at least one year (s. 147(4), (5)).


The couple separated and she now is trying to threaten him with having to keep the kids 50% of the time and pay child support and they're not even really his children.

Can she do this?

Yes. Absolutely, although actual parenting time orders have to be entered by a court in the best interests of the child, and 50% is not a magic number in that regard.

More generally, children are "really your children" even if you aren't biologically related to them under Colorado law. Someone does not have to be biologically related to a child to be their legal father.

In Colorado, a man is presumed by law to be the father if the man consents to having his name placed on the birth certificate of a child of his wife after the children is born, even if the marriage took place after the child was born.

(1) A man is presumed to be the natural father of a child if: . . . (c) After the child's birth, he and the child's natural mother have married, or attempted to marry, each other by a marriage solemnized in apparent compliance with law, although the attempted marriage is or could be declared invalid, and: . . . II. With his consent, he is named as the child's father on the child's birth certificate[.]

Colo. Rev. Statutes § 19-4-105.

In Colorado, and most other jurisdictions there is a statute of limitations from the birth of the child to contest paternity established by a birth certificate. In Colorado that is five years. In some jurisdictions it can be as little as two or three years.

(1) A child, his or her natural mother, or a man presumed to be his or her father pursuant to section 19-4-105 (1)(a), (1)(b), or (1)(c) or the state, the state department of human services, or a county department of human or social services, pursuant to article 13 or 13.5 of title 26 or article 5 of title 14 may bring an action: . . .

For the purpose of declaring the nonexistence of the father and child relationship presumed under section 19-4-105 (1)(a), (1)(b), or (1)(c) only if the action is brought within a reasonable time after obtaining knowledge of relevant facts but in no event later than five years after the child's birth. After the presumption has been rebutted, paternity of the child by another man may be determined in the same action, if he has been made a party.

Colo. Rev. Statutes § 19-4-107.

If the conditions for the five year statute of limitations applies, other statutes of limitations that would otherwise seemingly also apply cannot be utilized. See e.g., People ex rel. S.L.H., 736 P.2d at 1228; see also M.R.D. by P.D. v. F.M., 805 P. 2d 1200, 1201-03 (Colo. App. 1991).

If the children are six years old, the statute of limitations to disestablish the paternity of the father listed on the birth certificate shortly after the children were born has passed and the presumption of paternity is conclusive and cannot be rebutted with even conclusive evidence of a lack of a biological relationship between the father and the child.

The statute of limitations is longer in cases in which no man has been established to be, or is presumed to be, the father of the child, or when the basis of the presumption of paternity one of several grounds which are each different than the one in this case. But, that isn't the situation in this question.

Also, if the man agreed knowing the facts, he may be estopped from changing his position later on even if he contests paternity in a time frame consistent with the statute of limitations. See generally, Colo. Rev. Statutes § 19-4-105(2).

Furthermore, only certain people are allowed to bring suit to raise the issue that the husband of the mother is not the father - only the mother, the legally recognized father-husband, or the child (through a guardian ad litem). In the fact pattern of this question, "the other man" or his relatives are not allowed to bring a lawsuit to have the paternity of "the other man" (a provision of the law that the U.S. Supreme Court has held to be constitutional in a case arising in another state). The government also lacks standing to bring a lawsuit in it own right to declare that the father-husband is not the child's parent.

Child support is owed by the legally recognized father of a child regardless of the existence or absence of a biological relationship to the child, unless at least such time as a court determines that this person is not the legal father of a child. And, often due to a conclusive presumption or a statute of limitations the legal father's paternity can't be disputed at all.

The substantive and most of the procedural details are spelled out in the Colorado Uniform Parentage Act.


A person is presumed to be a father (with all the rights and liabilities this entails) if the:

  • person is named as the father on the birth certificate or adoption certificate
  • person signs a statutory declaration (a legal document) saying he is the father
  • child was born during the marriage or period of living together
  • person lived with the mother at any time in the period between 44 weeks and 20 weeks before the birth of the child
  • court makes an order or finding that identifies a person as the father of the child.

You score a 3/5 so you are the father.

Of these, the last is definitive and overrides the other four, however, the Family Court will only order a paternity test on application, where parentage is seriously in doubt, and if it is in the best interests of the child(ren).

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    – Dale M
    Commented Mar 23, 2023 at 8:50

German law says, in §1592 BGB:

The father of a child is the man

1.  who is married to the mother of the child at the date of the birth,

2.  who has acknowledged paternity or

3.  whose paternity has been judicially established under section 1600d or section 182 (1) of the Act on the Procedure in Family Matters and in Matters of Non-contentious Jurisdiction [Gesetz über das Verfahren in Familiensachen und in den Angelegenheiten der freiwilligen Gerichtsbarkeit].

In OPs case, being on the birth certificate clearly fulfills 2. of acknowledging paternity. So, the question of biological parenthood is irrelevant.

Interestingly, the father can't just get a genetic test, claim he's been falsely "made" the father when in reality he isn't, and abandon fatherhood. A genetic test is deemed highly personal information which can only be done when the person agrees, or in case of a minor, all legal guardians agree. In order to legally fight parenthood, the father would have to file a lawsuit, establish evidence (that wasn't known at the time of establishing fatherhood), with an illegally obtained DNA test not being admissible, in which case the court might order a DNA test to be conducted. So, renouncing your fatherhood is not completely impossible, but very hard to do.

More about this, in German, here.

As to the question "can she make him do this" (spend time with the kids, pay for them): yes she can. Both parents share the "Sorgerecht" (custody), which can only be given up under specific circumstances.

The mother can apply for sole custody, which will generally be granted if the father agrees, so this is a way of getting rid of custody but needs the mother's cooperation. This will not have an effect on the father's duty to pay child support, however. The only other option would be neglecting the kids to an extend that makes the Jugendamt (CPS) revoke custody, but this is unlikely to be possible without committing some crimes that would make the endeavor counterproductive. Link (in German again)

  • 1
    OP said that the children are now six and your link said that the time span during which you can try to revoke fatherhood are two or five years.
    – Jan
    Commented Mar 18, 2023 at 16:39
  • Correct, there's a lot more ifs and buts than I was willing to explain in my post, and as the OP isn't in Germany all of this isn't directly relevant to OP either. What I wanted to explain is that it's very hard to get rid of fatherhood, and "just get a test that proves you're not the biological father" won't do. I hope I got that point across. Commented Mar 18, 2023 at 19:50

Depending on specific facts, Q (the man in question) is legally a presumed parent under RCW 26.26A.115 because "The individual resided in the same household with the child for the first four years of the life of the child, including any period of temporary absence, and openly held out the child as the individual's child" (feel free to correct that). A assume the two were just living together and there was no legal marriage or state registered domestic partnership. Note that "presumed parent is a specific kind of legal parent relation.

There is also an "adjudicated parent" RCW 26.26A.400-515 which involves going to court to have Q declared to be a parent (I assume that didn't happen, you didn't mention it). Then there is an "acknowledged" parent per §200 where a would-be acknowledged parent and the woman who gave birth to a child "may sign an acknowledgment of parentage to establish the parentage of the child". This is generally required in the kind of case that you describe, in order to "put Q on the birth certificate". Things are a little tricky if B (biological father) was married to the woman or in a legal relation with the female, but you didn't mention that so I assume the acknowledgement was not illegal.

RCW 26.26A.235 states how either party the mother can rescind the acknowledgment of parentage – a form and a court hearing. This does not obliterate the fact that Q is the legal father of the children, and the mother can petition for child support on that basis. It is unlikely that the court would order a person to take 50% custory when they want 0% custody and the mother is at least willing to have full custody. On the third hand, if both parents are being obstreperous, the court might speak harshly to them and order a 50-50 custody and support arrangement.


You seem to have ties to North Carolina. The following quotes are from https://www.northcarolinadivorcelawyersblog.com/fathers-natural-legal-and-presumed/:

If the mother is married at the time of birth, the husband is the presumed father:

A presumed father is the husband of a person who gives birth to a child during the course of marriage to the husband. This father is presumed to be the natural father, but this is a rebuttable presumption.

If the biological and the legal father are not the same person:

If the natural father has not taken any action to establish paternity, then the father married to the mother is still the presumed father. However, actions to establish paternity may also be brought by the director of social services if and only if the child is likely to become a public charge. [...]

To say the least, this area of law is very nuanced.

I like the last sentence.

https://www.arnoldsmithlaw.com/paternity-fraud.html has another bit of information:

If the mother is married to someone who is not the child’s biological father: North Carolina law requires that a mother’s husband be listed as the father on the child’s birth certificate. Even if the biological father voluntarily signs the Affiant of Parentage, this does not establish his paternity in this circumstance. A hearing will be held and the judge, after considering the evidence, will rule on paternity.

Again, it seems that the biological father needs to contest the legal fathership of the husband. I understand that the legal father cannot unilaterally rescind fathership.

Assigning fathership to the husband at time of birth is the rule in the vast majority of jurisdictions inside and outside the U.S. In all jurisdictions it is not trivial to change fathership. The motivation for this automatism is to provide an unambiguous legal situation which gives security to the child and their mother, and, to a lesser degree, to the husband. Clearly, the marriage's goal is to establish a family with the privileges and responsibilities that come with it, and the law makes this as clear as possible.

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