What is the ruling on a male doctor specializing in obstetrics and gynecology?

A man's specialization in gynecology and obstetrics is limited by the availability of female specialists in this field. If they are sufficient to meet the need, then it is not permissible for a man to specialize in it or to examine women. However, if the number of female specialists is insufficient and there is a need for a man to specialize in this field, then it is permissible for him to do so, and he is allowed to examine a woman's body only out of necessity.