Most people have 20 chromosomes, but the presence of an extra 21st chromosome creates the disorder.

绝大多数人拥有20对染色体，然而多出的另一对染色体会导致该疾病的产生。

The condition is created by a 21st, extra chromosome being replicated three times, thus causing the condition.

该疾病是由于人体的第21对染色体的三体变异所造成的。

Klinefelter syndrome develops when a gamete, either sperm or egg, contains at least one extra X chromosome.

异常在配子时期就存在了，精子和卵子都有可能发生，异常的配子会多出至少一条X染色体。

Either way the separation doesn't happen and the end result is a gamete with an extra X chromosome.

不管是哪种情况，都发生了不分离的现象，最后的结果都是产生了多一条X染色体的配子。

Multiply by two, and the final result is 2 cells with an extra chromosome, and two cells missing a chromosome.

（第二次减数分裂后）细胞数量乘以2，最终结果为两个具有额外染色体的细胞和两个缺少一条染色体的细胞。

This extra chromosome results in the features of Down's syndrome.

这条额外的染色体导致了唐氏综合症的特征。

Now, they never claimed that the individuals with an extra X chromosome were superfemales.

现在，他们从未声称拥有额外 X 染色体的个体是超级女性。

(Audio) SR: Going back and looking at those original findings in that high-security psychiatric institution, they had also found a high number of individuals with an extra X chromosome.

（音频）SR：回头看看那个高度安全的精神病院的最初发现，他们还发现大量个体有一条额外的 X 染色体。

And they find a number of people who are XYY. And according to Sarah: (Audio) SR: They just rushed to publish a theory suggesting that this extra Y chromosome could explain criminality in some men.

他们找到了一些 XYY 的人。根据 Sarah 的说法：（音频）SR：他们只是匆忙发表了一个理论，表明这个额外的 Y 染色体可以解释某些男人的犯罪行为。

Normally, each egg and sperm cell contains 23 chromosomes, and, when they unite, 23 pairs or 46 in total. Occasionally, an accident occurs when the egg or sperm cell is forming, creating an extra chromosome number 21.

正常情况下，每个卵子和精子细胞包含 23 条染色体，当它们结合时，共有 23 对或 46 条染色体。偶尔，当卵子或精子细胞形成时会发生意外，从而产生额外的 21 号染色体。