A theory might invoke dominant and recessive genes to explain how brown-haired parents ended up with a red-headed child, or use gravity to shed light on the parabolic trajectory of a baseball.

一个理论可能会引入显性和隐性基因来解释为什么棕色头发的父母 会生出红色头发的小孩，或者运用重力来阐释棒球的抛物线轨迹。

So, we know if you have offspring with someone genetically close to you like a sister or a cousin, it might mean that the child inherits two recessive genes.

所以， 我们知道， 如果您的后代与遗传上与您亲近的人（ 如姐妹或表亲）生育， 这可能意味着该孩子遗传了两个隐性基因。