Board Thread:Movie discussion/@comment-27198647-20151129152941/@comment-1259419-20170206211721

KKAGSOM wrote: If they wanted all the dinosaurs to be one gender, why didn't they make them all male? Henry Wu explains it all in the lab scene. He says that all vertebrates basically start as females. It is just when an additional sex hormone becomes active in some embryos (with male sex-chromosomes) change in development. That one hormone is easily blocked. By InGen's scientists.

Think of humans. The basal gender is female. You need an additional type of chromosome, theY-chromosome, to make a male. The fact that males start out as females is the reason males have nipples or a.

It is much more difficult to make all the embryos of the gender they do not start with.

Reality note: this is how gender-determination works in mammals. In birds (and probably other theropods) the basal gender is male. Birds need an additional kind of chromosome to make a female. In the other dinosaur groups, brontosaurs and ornitischia, it is unknown how the gender was determined.