"Biological father" means a man who was not married to the mother when the child was born and who has acknowledged his paternity in open court, or who has signed a statement acknowledging paternity, or who is legally presumed to be the father because he married the child's mother after the child's birth and his name appears on the child's official record of birth, or whose paternity is adjudicated in court. When paternity has been established in the above manner, the relatives of the biological father as well as those of the mother may be considered for the placement of related children. (R 301, 302, 304)