Only cardiovascular tissues associated with one male pup per litter per measured outcome variable were used to control for sex and within - litter variation. (journals.plos.org)
Also realize they are not «sex specific» and there can be a significant difference between the weight of a female and male pup at the same age. (meisterhunde.com)
Some breeders will price male pups higher because they saw peers doing it, and won't really understand the reasons why. (breedingbusiness.com)