Quote Originally Posted by Evan Jamison
Only one sperm per baby produced. If on the off chance that two sperm did make it into the egg at the exact same moment (very highly unlikely), there would be too many chromosomes inside, 3n instead of 2n, and the egg would not survive. There can be multiple fertilized eggs inside one shell though; fraternal twins sharing the same eggshell.

-Evan
exactly. not possible.