Can sperm from two different men fertilize the same egg?
in dogs, yah. In people, no. No. 2 sperm from one man cannot
fertilise one egg, this would give the embryo too many chromosomes
and it would not be viable. Sperm from 2 different men can
fertilise two eggs released at the same time and you get fraternal
twins from two different fathers. I would be more worried about
sexually transmitted diseases than pregnancy if I were you.