*Male mice can develop ovaries if their moms don’t get enough iron during pregnancy!* 🐭💡 A new study published in Nature for the first time has showed a *simple dietary change* can override *sex determination* in mammals. If a pregnant mouse doesn’t get enough iron, some of her genetically male (XY) babies can actually develop as females—with ovaries instead of testes! _How does this happen?_ • Normally, the Sry gene on the Y chromosome triggers male development, but this process depends on an iron-powered enzyme called KDM3A. • If the mother is iron deficient, KDM3A can’t activate Sry. The result is that some male embryos develop ovaries or even mixed sex organs. So there it is, nutrition during pregnancy is more powerful than we ever imagined!!! *Iron deficiency affects over a third of pregnant women* globally, raising questions about its possible effects on human development.