Estrogen and vitamin D activate the gene for serotonin production (TPH2), potentially explaining higher autism prevalence in males.

“estrogen also activates this this Gene so there's sort of a a a a backup mechanism in in female fetuses it's been shown from anionic fluid that female fetuses have higher levels of estrogen they also have higher levels of estrogen neonatally right after birth so it's possible that if a mother is deficient in vitamin D and she's carrying a female child there's a backup system because that estrogen is able to activate the same gene that vitamin D activates but if it's a male fetus they don't have that backup system”