I have found in general my female pups have a bit harder time with it - physically it seemed - particularly in the morning when let out of their crate - I had to immediately scoop them up and put them outside -whereas the male pups have always looked at me like I have gone mad and they wander around a bit before peeing -the female pups have all immediately squatted - I had a vet tell me it was a physical difference in the females from the males which made it harder (I have no idea if that is true - but it helped my frustration with it)