Science question of the day

Ok suppose two identical twins have sex with a woman only hours apart, and she becomes pregnant, is there a way to trace the father? Obviously the standard DNA tests will not work, but are there any epigenetic alternatives? One of the problems is that methylation of the genome is reset at an early embryonic stage. While there may be imprinting, is it possible to match it to the father's "consensus" sperm imprinting, or is it sperm cell specific? Any ideas?