Are there any Sharia texts in the Qur’an or the Sunnah that prohibit or permit a man working as an obstetrician-gynecologist?

The general rule is that a woman treats a woman and a man treats a man. However, the reverse is permissible in cases of necessity or need. This includes a woman's need for a male doctor in obstetrics for treatment or consultation due to his expertise. The physician should be mindful of Allah Almighty's constant watch, the gravity of the responsibility, and the trust placed in him. It is not easy for a husband to change his medical specialization, which requires effort, time, and money. Therefore, he has leeway to work in his initial specialization while observing the Sharia-compliant guidelines.