I know the whole x and y chromosome and the father and sperm decide. What I am wondering is if there is something that makes one sex more prevalent than the other. This year we have had 100% bucklings, 75% bull calves and weaned over 70% boar (barrow) pigs. Now the laws of average should have made it closer to 50 50 I would think. I have had 3 litters of pigs that were all male in the litter but NEVER had a litter of all females. For my feeders I really don't mind at all but it sucks for my registered pigs and my dairy goat kids.