All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Test-tube baby is permissible only upon necessity. However, it is stipulated that the sperm and the egg are taken from the same couple and that the fertilized egg is planted in the womb of the woman from whom it was taken in the first place. Thus, it isn`t permissible to plant the egg in the womb of another woman, even if she is a wife of the same husband. This is because such a thing would lead to great evils on the level of rights and ethics.
In its 3rd meeting (1407 H, corresponding to 1986), the Islamic Fiqh Assembly issued Resolution No.(16). It states:
" The following five methods are prohibited and totally banned for themselves or for their consequent effects, such as mixing of the sexes and wasting of motherhood and other……The fifth method: Conducting external fertilization using husband`s sperm and first wife`s egg, then planting that fertilized egg in the womb of the second wife." And Allah The Almighty Knows Best.