Why is it that masturbation is not ruled permissible for an unmarried man for the purpose of medical tests, except in the absence of a religiously lawful alternative, whereas it is ruled permissible for a married man for the same purpose without drawing attention to the possibility of seeking his wife’s assistance?

Masturbation is forbidden, and there are previous fatwas that clarify its prohibition and the means to abstain from it. Masturbation is permissible for medical tests when necessary and no other means are available to extract semen. However, if semen can be extracted by other means (such as masturbation by the wife for a married man), then it is not permissible at that time.