Transgender man receiving testosterone treatment became pregnant and delivered a girl: A case report.

Many transgender men receive testosterone therapy to achieve virilization. The therapy is often mistaken for having a contraceptive effect because it causes amenorrhea. However, some treated patients become pregnant, which is not well known. A 25-year-old transgender man who had received testosterone for 3 years had an unplanned pregnancy during discontinuation of treatment. He was unaware of his pregnancy, resumed testosterone, and continued treatment until pregnancy was confirmed. His female child was exposed to androgens during the fetal period; thus, careful, long-term observation was required. He developed insomnia and depression during the postpartum, and giving birth made it difficult for him to change his family register to male. Transgender men can become pregnant through sexual intercourse with biological men, even during hormone replacement therapy, so correct contraception is necessary to avoid unwanted pregnancies. Transgender sex education is important to increase awareness of this issue among individuals and medical professionals.