B.  Presumed Fathers

C.R.S. § 19-4-104
A legal parent-child relationship is established between a mother and child by proof she gave birth to the child. It is established for adoptive parents by proof of adoption. For fathers, it is established by legal presumption or court determination.

C.R.S. § 19-4-105(1) and (2)(a)
N.A.H. v. S.L.S., 9 P.3d 354 (Colo. 2000)
1.  Standard for Weighing Presumptions

Under certain conditions, a man is a “presumed father.” This presumption may only be rebutted by clear and convincing evidence. If two or more presumptions conflict, policy and logic must yield to the best interests of the child standard when deciding legal fatherhood. 


N.A.H. v. S.L.S., 9 P.3d 354 (Colo. 2000)
In N.A.H., the Colorado Supreme Court held that the best interests of the child was the proper standard to consider where there are competing presumptions of legal fatherhood. The mother and husband were married at the time of the child’s conception and birth, and the husband was listed on the child’s birth certificate. Mother had become involved in an extramarital affair with a coworker, who was the child’s biological father. The court held that the magistrate or judge should apply the best interests of the child standard, and exercise discretion by taking into account all the facts and circumstances of the case, to determine paternity.

C.R.S. § 13-25-126(1)(g)
Paternity is presumed when the man has at least a ninety-seven percent probability of paternity. 

R.McG. v. J.W., 615 P.2d 666 (Colo. 1980)
In R. McG., the Colorado Supreme Court held that a man had standing to establish his paternity even though the mother was married to another man at the conception and birth of the child. Genetic testing showed the man had a 98.8% probability of parentage.  The court held that equal protection mandated his standing, since the mother could have filed an action against him under the Uniform Paternity Act, even though she was married.



2.  Presumptions of Paternity

Paternity is presumed when a father is:

  • Married to the mother before the child’s birth, and the child is born during the marriage;
  • Married to the mother after the child’s birth, and acknowledges paternity in writing;
  • Married to the mother after the child’s birth, and consents to be named on the birth certificate;
  • Married to the mother after the child’s birth, and is obligated to support the child under a court order;
  • Married to the mother after the child’s birth, and has signed a written agreement to support the child;
  • Divorced from the mother before the child’s birth, but the child is born within 300 days of dissolution;
  • A marriage is voided before the child’s birth, and the child is born within 300 days of court invalidation;
  • An invalid marriage ends before the child’s birth, and the child is born within 300 days of the end of cohabitation;
  • Not married to the mother after the child’s birth, but acknowledges paternity in writing;
  • Not married to the mother after the child’s birth, but genetic tests show 97% or more probability of parentage;
  • Not married to the mother before the child reaches the age of majority, but receives the child into his home and openly holds out the child as his birth child.
C.R.S. § 19-4-106
After artificial insemination, the mother’s husband is the legal father by statute. The donor is not. 

In the Interests of R.C., 775 P.2d 27 (Colo. 1989)
If the mother is unmarried, and agrees the donor will be treated as a father, the statute eliminating his parental rights does not apply.