Simple Doubt Regarding Breast-feeding Does Not Invalidate the Marriage
Question :
A man married his maternal uncle's daughter, and she bore him five children. After this period of time, the members of his family and his mother began to talk, and she remembered that she had breast-fed his wife when she was nine months old. At first, she said that she had breast-fed her once, and after she was pressed to remember and to speak truthfully, she said that she does not remember whether it was one time or more, because it was a long time ago twenty years have passed. So what should the husband do in this situation?
Answer:
The husband should not do anything in this situation.
Breast-feeding is not confirmed unless it occurs five times during the first two years of life and before weaning. Anything other than this does not cause prohibition, nor are any of the rulings of breast-feeding confirmed by it. But if there is any doubt over whether the breast-feeding amounted to five times or less than five times, then the basic principle is that it is not confirmed, and there is no prohibition in that case.
But it is more prudent not to marry her if there is doubt.
However, if the marriage has already taken place and theThe Book of Breast-feeding contract was made in a correct manner, then he is not obliged to part from her since there is nothing definite to invalidate it. So the contract is now confirmed and sure, while the thing which would invalidate it is not sure; and something which is sure is not abandoned for something which is not sure. Therefore, in this case, he should remain with his wife and there is no sin upon him, unless the mother remembers later that she breast- fed this wife five times or more during the breast-feeding period in which prohibition is confirmed. In that case, it will be clear that the contract is invalid, he would be obliged to part from her, and any children born would be legitimately attributed to the man, because they were created from the water (i.e. sperm) of a man who believed that he had fulfilled the requirements of the Islamic Law.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 6 Pages 144-145