C.  Acknowledgement of Paternity


C.R.S. § 19-4-105(1)(e)
A man may voluntarily acknowledge paternity. The acknowledgment must be in writing. It must be filed with the court or registrar of vital statistics. The mother must be given notice. She must file a written challenge with the court or registrar within a reasonable time if she disputes his claim.

C.R.S. § 19-4-105(1)(e)
If another man is the presumed father, the acknowledgment may only go into effect if he consents, or the presumption is rebutted. 

C.R.S. § 19-4-105(2)(b)
It becomes a legal paternity finding sixty days after its execution. The acknowledgment of paternity goes into effect sooner if it is part of a paternity or child support action involving the signing party.

K.H.R. v. R.L.S., 807 P.2d 1201 (Colo. App. 1990)
The court may grant a motion for summary judgment excluding a presumptive father, on the basis of blood tests showing another not being excluded.