[lisatodd]

i do think the female determines the amount of puppies. i think each litter can be different. i have seen many times on here where the bitch has whelped differently each time.

i can tell you this.....i hope i explain it correctly

the bitch is fertile for approx 5 days
during this time, she can drop approx 200 eggs
the sperm will travel up to the eggs
then the eggs come down and attach themselves to the wall of the uterus
depending on how many attach themselves to the wall then this will be litter
the rest is then absorb in the body

** i am sure someone else could explain this better than me

i hope this helps somewhat