DNA testing. It's highly unlikely if at all possible for each of them to have a different father. I imagine you would either have released 2 eggs and both were fertilized or 1 egg was fertilized by more than one sperm, which I'm not sure is possible.
A gang train? Really? Where is your self respect? As a living being deserve better than that.
eddie
it's not possible for an egg to be fertilized by two sperm, once a sperm enters the cell surface membrane changes it's permeability so another sperm cant get in; this is due to the cell dividing with all of the dna inside, so if there were three sets of DNA you would get a very odd baby. It is also very unlikely that two eggs came out at once, though still possible. What is more probable is that the egg split during it's early 8 cell miotic stage and formed two twins.