The eminent Muslim scholar and renowned Da`iyah, Sheikh `Abdel Khaliq Hasan Ash-Shareef, states:

“1. We do not know the number of Prophet Adam’s children and it is not an act of worship to know their number nor there is a benefit beyond that.

2. In the lifetime of Adam and Eve (peace and blessings be upon them) it was permissible for Adam’s son to marry his sister and through this way humankind grew in numbers and spread through the earth. Almighty Allah says, ‘O mankind! Be careful of your duty to your Lord Who created you from a single soul and from it created its mate and from them twain hath spread abroad a multitude of men and women.’ (An-Nisaa’ 4: 1).