Is dating your cousin wrong
Other factors that contributed to the decrease in cousin marriage include changing social norms, shrinking family sizes, and the increasing autonomy of women.
Cousin marriage became a taboo after it had been the norm for its usefulness in keeping money in the family.
This drops the further away the relation is to the person.
Sharing a number of genes is not good for preventing genetic diseases.
Family sizes were much larger increasing the chances of being related to someone else.
Hamish Spencer, head of zoology at the University of Otago in New Zealand told Scientific the elevated risk is "comparable to a 40-year-old woman having children and we consider that perfectly acceptable.
"I can't imagine a law saying they're not allowed to have children." Marrying a first cousin is a common practice in the Pakistani community.
And a study carried out in Bradford where there are a high level of Pakistanis living, showed that birth defects are increased when two family members procreate.
Marriage between first cousins more than doubles the chance of having a child with potentially life-threatening defects, it showed.