I once made this breeding and this breeding at the same time (Gr Ch Sparky x Screamer and Ch Stormbringer to Screamer).

The result?

0 Stormbringer pups
1 Gr Ch Sparky pup

I later learned that 2 different loads of sperm were antagonistic to each other (each trying to "kill" each other).

That, plus the fact both dogs were almost sterile, got me 1 pup out of 2 studs.

I never did a DNA, because 1) my pup was black, so it was genetically-impossible for it to be a Stormbringer pup, and 2) she was a clone of Gr Ch Sparky, and only a blind man couldn't see that.

Jack