Paternity- Presumed Father. A man who is married to the mother when the child is born or who was married to the mother within 301 days of the birth of the child, whether or not the marriage later was declared invalid; or he married the mother after the child was born and voluntarily signed the birth certificate or.... For more information, check out my Paternity Series at http://ping.fm/QGAH9 beginning Saturday, April 17, 2010.