And also vets have different conclusions and opinions about this
A vet I know told me it was coming form one side: the male.
And later on he had in his kennel a male with missing both testicles. And by accident this dog had mated (because he did not expect ist was possible
)
And surprise, surprise, there was a litter of 5 and all the 3 males were normal
And also all the offspring of this litter and their offspring had two testicles
And now the same vet is telling everyone the possibility comes from tow sides and a bit more from the female
greetings
Mijke