What is the ruling on transferring reproductive organs between individuals, and does it cause mixing of lineages? What is the ruling on transplanting organs that are not of their natural size through genetic engineering? And is it permissible to use cloning on animals?

A number of scholars and researchers have concluded that it is impermissible to transplant reproductive organs from one human to another, justifying this with several reasons, including:

1. The testes and ovaries contain the secret of heredity and procreation, which would result in the offspring belonging to the donor. This leads to the mixing of lineages (nasab) and resembleszina (fornication/adultery).

2. Testicular transplantation means the transfer of sperm from the donor to the recipient.

3. In the case of a transplanted penis or vagina, subsequent intercourse would be forbidden and akin to zina; because the man would be engaging in intercourse with a vagina he does not rightfully possess, and the woman would be intercoursed with a penis belonging to someone other than her husband.

4. The presence of doubt regarding the mixing of lineages, as it would be unknown whether the developing pregnancy originated from the donor's or the recipient's genetic material.