It has long been thought that this breast development in newborns is due to female hormones powder (oestrogens) in the mother's body passing through the placenta during pregnancy and stimulating breast development in the baby.
Kuye kwacatshangwa ukuthi lokhu kuthuthukiswa kwebele kusana olusanda kuzalwa kubangelwa amahomoni wesifazane i powder (ama-oestrogen) emzimbeni womama odabula i-placenta ngenkathi ekhulelwe futhi evuselela ukuthuthukiswa kwebele emntwaneni.