After amendments adopted in 2002, the Uniform Parentage Act retains all but one of the original presumptions of paternity contained in UPA § 4 (1973). Originally the 2000 version of the new Act limited presumptions of paternity to those related to marriage. The objection by the ABA Steering Committee on the Unmet Legal Needs of Children and the Section of Individual Rights and Responsibilities that this could result in differential treatment of children born to unmarried parents resulted in the revision to this section.

Subsection (1) deals with a child born during a marriage; subsection (2) deals with a child conceived during marriage but born after its termination; subsection (3) deals with a child conceived or born during an invalid marriage; and, subsection (4) deals with a child born before a valid or invalid marriage, accompanied by other facts indicating the husband is the father.

Added by amendment in 2002, subsection (5), is a significant revision of UPA § 4(4) (1973), which created a presumption of paternity if a man "receives the child into his home and openly holds out the child as his natural child." Because there was no time frame specified in the 1973 act, the language fostered uncertainty about whether the presumption could arise if the receipt of the child into the man's home occurred for a short time or took place long after the child's birth. To more fully serve the goal of treating nonmarital and marital children equally, the "holding out" presumption is restored, subject to an express durational requirement that the man reside with the child for the first two years of the child's life. This mirrors the presumption applied to a married man established by § 607, infra. Once this presumption arises, it is subject to attack only under the limited circumstances set forth in § 607 for challenging a marital presumption, and is similarly subject to the estoppel principles of § 608.

One presumption found in UPA (1973) is not repeated in the new Act. Former UPA §4(5) created a presumption of paternity if the man "acknowledges his paternity of the child in a writing filed with [named agency] [and] the mother does not dispute the acknowledgment within a reasonable time." This presumption was eliminated because it conflicts with Article 3, Voluntary Acknowledgment of Paternity, under which a valid acknowledgment establishes paternity rather than a presumption of paternity.

Finally, subsection (b) is a complete rewrite of UPA (1973) § 4(b). The requirement that a presumption "may be rebutted only