Different shark species have three modes of reproductive development: viviparous (giving birth to live young), oviparous (laying eggs in egg cases, to hatch on the sea floor), and ovo-viviparous (retaining egg cases in the uterus to hatch, and bearing live young). This differs from most bony fish, which produce millions of eggs at once.
母與子鯊魚的生殖分為胎生、卵生、卵胎生三種。與其他硬骨魚類一次產卵上百萬顆大異其趣的是，屬於軟骨魚類的鯊魚力行「家庭計畫」，目前已知許多種類的鯊魚每胎只產下十隻不到的幼鯊。