A father is the male parent of a child. Besides the paternal bonds of a father to his children, the father may have a parental, legal, and social relationship with the child that carries with it certain rights and obligations. An adoptive father is a male who has become the childs parent through the legal process of adoption. A biological father is the male genetic contributor to the creation of the infant, through sexual intercourse or sperm donation. A biological father may have legal obligations to a child not raised by him, such as an obligation of monetary support. A putative father is a man whose biological relationship to a child is alleged but has not been established. A stepfather is a male who is the husband of a childs mother and they may form a family unit, but who generally does not have the legal rights and responsibilities of a parent in relation to the child. The adjective "paternal" refers to a father and comparatively to "maternal" for a mother. The verb "to father" means to procreate or to sire a child from which also derives the noun "fathering". Biological fathers determine the sex of their child through a sperm cell which either contains an X chromosome (female), or Y chromosome (male). Related terms of endearment are dad (dada, daddy), baba, papa, pappa, papasita, (pa, pap) and pop. A male role model that children can look up to is sometimes referred to as a father-figure.
Dolphin fathers help in the care of the young. Newborns are held on the surface of the water by both parents until they are ready to swim on their own. A number of bird species have active, caring fathers who assist the mothers, such as the waterfowls mentioned above. Apart from humans, fathers in few primate species care for their young. Those that do are tamarins and marmosets. Particularly strong care is also shown by siamangs where fathers carry infants after their second year. In titi and owl monkeys fathers carry their infants 90% of the time with "titi monkey infants developing a preference for their fathers over their mothers". Silverback gorillas have less role in the families but most of them serve as an extra protecting the families from harm and sometimes approaching enemies to distract them so that his family can escape unnoticed.Many species, though, display little or no paternal role in caring for offspring. The male leaves the female soon after mating and long before any offspring are born. It is the females who must do all the work of caring for the young. A male bear leaves the female shortly after mating and will kill and sometimes eat any bear cub he comes across, even if the cub is his. Bear mothers spend much of their cubs early life protecting them from males. (Many artistic works, such as advertisements and cartoons, depict kindly "papa bears" when this is the exact opposite of reality.)