What is the ruling of Islamic law on the phenomenon of the spread of the "third gender" (a man transforming into a woman) and the "fourth gender" (a woman transforming into a man) through the intake of hormones, and the subsequent plucking of eyebrows and application of makeup?

The phenomenon of gender reassignment has two cases:

1. First Case: If reliable medical reports prove that a person possesses reproductive organs contrary to their outward appearance, then there is no objection to performing a gender reassignment surgery. 2. Second Case: If medical reports prove that a man possesses male organs and a woman possesses female organs, then gender reassignment in this case is Haram (forbidden) without dispute, whether through surgery or hormones.

As for a man applying makeup specifically for women, it is Haram in all cases, due to its resemblance to women, and this is considered one of the major sins.