👶 Why do men have nipples? Because milk evolved over 100 million years before nipples did. A 300-million-year story in four parts: sweaty-bellied synapsids hydrating eggs, a lysozyme gene accidentally inventing lactose, monotremes dripping milk through belly fur, and a PTHrP mutation that finally pulled ducts into a bud.
🐦🔥nemo™🐦⬛ 🇺🇦🍉
in reply to jcrabapple • • •I have read nipples in men are present because embryos develop the same basic mammary structures before sex-specific hormone effects later shape breast development.
Early embryos have their genetic sex set by chromosomes right after fertilization, but their bodies don’t become clearly male or female until later when hormones and developing gonads shape their anatomy.
#nerdsh xD hahah
Wintergreen
in reply to jcrabapple • • •🐦🔥nemo™🐦⬛ 🇺🇦🍉
Unknown parent • • •C.W. Williams 🇺🇦 🌊🇨🇦🦑🇬
in reply to jcrabapple • • •youtu.be/1viWDlbxAsc
- YouTube
youtu.beC.W. Williams 🇺🇦 🌊🇨🇦🦑🇬
Unknown parent • • •