monozygotic and dizygotic

Psychology Made SimpleのAbnormal Behaviorsの章にあった文章です。
There are two types of twins: monozygotic, or identical twins, and dizygotic, or fraternal twins. Identica twins originated as one egg that divided into two embryos. They have the exact same genetic composition. Fraternal twin started as two eggs and are not more genetically similar than any other sibling pair.
一卵性双生児、二卵性双生児を英語でなんて言うか全く知りませんでしたがこの文章を読めば辞書をひかずとも分かりました。