On the other hand, why are so many crystallographers women? Dorothy Hodgkin, Olga Kennard, Eleanor Dodson, Kathleen Lonsdale, it's easy to come up with all these and many more, they are among the greats.
You'd think it's due to J D Bernal. He was a pioneer of x-ray crystallography and was involved with many women, all of whom he treated with respect. That set the tone in the field.