1. 因为古代的时候，家族过于庞大，有太多的表兄表妹看，这些表兄表妹或许都没有血缘关系了，就算稍微亲近一点了，也不一定代表血缘关系就非常亲近，而不是了真的兄妹那样，具有很深的血缘关系，我们所说的是亲兄妹结婚，容易生出智障儿童，但并不代表表兄妹结婚，也容易生出智障儿。

1. Because in ancient times, families were too large, and there were too many cousins to keep an eye on, these cousins might not even have a blood relationship. Even if they are slightly closer, it doesn't necessarily mean that their blood relationship is very close, as opposed to being real siblings who have a deep blood relationship. What we are talking about is that the marriage of full siblings is likely to produce children with intellectual disabilities, but this does not necessarily mean that the marriage of cousins is also likely to produce such children.

2. 我觉得正是因为表兄妹的血缘关系不够深，所以出生的后代智障儿比较少，这是一件值得高兴的事情。但是这并不代表现代人可以这样做，现代人表兄妹结婚，出生智障儿的可能性还是非常大的。毕竟古代的孩子多，很多表兄表妹，都是很远很远的远方亲戚，自然结婚生孩子就没有什么事情，但现代人做不到。

2. I believe that it is precisely because the blood relationship between cousins is not deep enough that the number of offspring born with mental retardation is relatively small, which is something to be happy about. However, this does not mean that modern people can do this. The possibility of giving birth to a child with mental retardation is still very high for modern cousins who marry each other. After all, in ancient times, there were many children, and many cousins were very distant relatives, so there were no problems with getting married and having children. But this is not possible for modern people.

3. 古代这样的情况也有可能出生智障儿，换句话说，有5个或6个孩子的表兄弟姐妹中，有可能有一个有精神障碍的孩子，其余是健康的。根据当时的社会状况，这些精神发育迟滞的孩子很难在成人时期生存，因为先天性疾病，在非常年轻的时候死亡，所以无法将疾病的基因传给下一代，因为过早的去世，导致我们见到的智障儿也就少了。

3. In ancient times, such cases were also possible, meaning that among the first cousins with 5 or 6 siblings, there might be one child with a mental disability, while the rest are healthy. According to the social conditions at the time, these children with developmental disabilities had a hard time surviving into adulthood due to congenital diseases, often dying at a very young age. Therefore, they were unable to pass on the genetic disease to the next generation, and because of their early deaths, the number of mentally disabled children we see today is relatively small.

4. 更有甚者，近亲婴儿死亡率仅为1%，表兄妹结婚生出来的孩子，畸形的婴儿并不大。研究显示，在下一代中，引发精神发育迟滞的可能与酒精和过度吸烟有关，个人的生活习惯仍然非常重要。总结来讲，在现在我不建议表兄表妹结婚。

4. Moreover, the infant mortality rate among close relatives is only 1%, and the children born from first cousins are not very deformed. Research shows that the possibility of causing mental developmental retardation in the next generation is related to alcohol and excessive smoking, and personal lifestyle habits still play a very important role. In summary, at present, I do not suggest that first cousins marry each other.