Snopes wrote:

• Claims spread that definitions of "male" and "female" included in a January 2025 executive order that asserted sex is established at conception accidentally classified all Americans as women. The claims were based on the common belief that all human zygotes and embryos begin as female.



• The current scientific understanding of sexual differentiation no longer holds that female is the "default" sex for embryos. Rather, as is the case for male embryos, evidence suggests the development of normal female sexual characteristics in mammals depends on certain conditions.