Reproductive endocrinology and infertility
Reproductive endocrinology and infertility (REI) is a surgical subspecialty of obstetrics and gynecology that trains physicians in reproductive medicine addressing hormonal functioning as it pertains to reproduction as well as the issue of infertility. While most REI specialists primarily focus on the treatment of infertility, reproductive endocrinologists are trained to also test and treat hormonal dysfunctions in females and males outside infertility.
Source: Wikipedia — Reproductive endocrinology and infertility (CC BY-SA 4.0)