Comprehensive care for transgender and gender nonbinary patients has been a priority established by the World Professional Association for Transgender Health. Because pubertal suppression, gender-affirming hormone therapy, and antiandrogen therapy used alone or in combination during medical transition can affect gonadal function, understanding the effects these treatments have on fertility potential is important for practitioners caring for transgender and gender nonbinary patients. In this review, we outline the impacts of gender-affirming treatments on fertility potential and discuss the counseling and the treatment approach for fertility preservation and/or family building in transgender and gender nonbinary individuals.