Islam does allow marriage between first cousins, even Prophet Muhammad(pbuh) wed his daughter Fatima to his cousin Ali, however couples breast fed by the same wet nurse are required to divorce.
I'm not asking this to question Islam or speak against the faith, just wondering as my marriage has recently been nullified because we were breast fed by the same nurse.
Marrying a first cousin, has some health risks for the children, especially repeated cousin marriages for generations.
In the first generation, its the same risk as a woman having children over 40, however risks rise with each generation, & in many Muslim communities, cousin marriages happen in practically evey generation. I have seen many families in Yemen where cousins are married in every generation.
There're problems in Saudi due to inbreeding:
Also, Pakistan has problems due to inbreeding:
Even in Britain, amongst immigrant Muslim communities, there're significantly more genetic illnesses than their numbers due to inbreeding:
So why is cousin marriage allowed?
But couples breast fed by the same wet nurse are ordered to divorce:
Sahih Bukhari Volume 3, Book 48, Number 828:
Narrated 'Uqba bin Al-Harith:
I married a woman and later on a woman came and said, "I suckled you both." So, I went to the Prophet (to ask him about it). He said, "How can you (keep her as a wife) when it has been said (that you were foster brother and sister)? Leave (divorce) her.
This poses no health risks to future offspring, yet its forbidden, but repeated cousin marriages do pose tremendous health risks.
Again, I ask this with sincere intention to know, I have seen repeated cousin marriages in Yemen & some genetic illnesses also.
Jazak' Allah Khair.