Updated Guideline and Terminology. The article, “Testosterone Therapy: Review of Clinical Applications” (October 1, 2017, p. 441) included a section titled, “Testosterone Therapy in Female-to-Male Transgender Patients” beginning on page 447, which was based on information from a 2009 Endocrine Society clinical guideline. At the time this article was written, an updated version of this guideline from 2017 was available but was overlooked by the authors. Based on information in the 2017 guideline, the text for this section of the article has been rewritten by the authors and some of the terminology was updated. The section title was also retitled “Testosterone Therapy in Transgender and Gender Diverse Patients.” The revised text reads as follows: “Testosterone therapy may also be used to facilitate gender transition for transgender men and gender nonbinary individuals desiring masculinization. Primary care physicians are increasingly involved in the initiation and management of testosterone therapy for this population. Although a full discussion of the use of testosterone for the treatment of gender incongruence is beyond the scope of this article, physicians can find concise guidelines in the 2017 Endocrine Society publication, “Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline,” at https://www.endocrine.org/guidelines-and-clinical-practice/clinical-practice-guidelines/gender-dysphoria-gender-incongruence.66” Reference 66 was also replaced with the citation for the updated guideline: Hembree WC, Cohen-Kettenis PT, Gooren L, et al. Endocrine treatment of gender-dysphoric/gender-incongruent persons: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2017;102(11):3869–3903. The online version of the article has been corrected.