As formulated in Bateman's principle, females have a greater initial investment in producing offspring (pregnancy in mammals or the production of the egg in birds and reptiles), and this difference in initial investment creates differences in variance in expected reproductive success and bootstraps the sexual selection processes.
Como se formula no principio de Bateman, as femias fan un maior investimento inicial na produción de crías (embarazo nos mamíferos ou produción de ovos nas aves e réptiles), e esta diferenza no investimento inicial xera diferenzas na varianza no éxito reprodutivo esperado e impulsa o proceso de selección sexual.