So in 1999 some woman in Montreal was dating an identical twin, who's understands himself to be the father of her child--and who's been acting as such, for five years, by paying child support and visiting the kid every other weekend--but has filed a paternity suit to be legally declared the father.
The twist: at the time the child was conceived, the woman says, she was hooking up with the other twin, too. For their part, the twins dispute the Even DNA tests may not reveal which brother is actually the father. For what it's worth, within the family, one's called 'papa,' and one's called 'uncle.' The woman's lawyer says, "The brothers are her friends and had sexual relations with her, but they were never together as a couple." Or, presumably, a threesome.
Paternity suit runs into double trouble [UK Observer]