A scientific study has revealed that marriage between partners who are closely related could lead to mental retardation, though sometimes the signs may not so be obvious.

The study was conducted by a lecturer in human genetics at the National Research Center in Cairo, who said that he conducted the study on 100 disabled subjects, and discovered that 76 of the disabilities could be traced to marriage between close relatives, self-pollination.

 Dr. Ashur attributed other reasons for such disabilities, such as the age at which a couple gets marriage, and also the use of over-the-counter drugs by a pregnant woman, without proper medical supervision.

 He said the only cure for such hereditary disabilities is through the mapping of the genes and isolating the disability causing ones, but added that the diagnosis has to be made well before the disease develops.