至于说它是一件好事，在相关个人或来自小族群人们的孩子中潜在的遗传疾病告诉我们，近亲繁殖通常不是好主意。

As for it being a good thing, the potential for inherited disease in children of related individuals, or people from small communities, tells us that inbreeding is generally not a great idea.

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(举例来说，假如大部分个体是由小部分的父母亲繁衍而来，他们更易受到遗传疾病的侵袭，甚至有可能让整个种群几乎在一次侵袭中全军覆没。)

if most individuals are bred from a small number of parents, they could be vulnerable to a genetic disease, potentially wiping out almost the whole population at once.

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例如在人们开始吸烟之前，肺癌多数是一种遗传疾病，然后便成为了主要因香烟导致的疾病。

For instance, lung cancer was mostly an inherited disease until people starting smoking, and then it became a disease that was caused mostly by cigarettes.

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