Initiation of Gender-Affirming Testosterone Therapy in a Lactating Transgender Man

Sara Oberhelman-Eaton, Alice Chang, Cesar Gonzalez, Andrew Braith, Ravinder J. Singh, Aida Lteif

Research output: Contribution to journalArticlepeer-review


Introduction: Transgender and gender diverse individuals may choose to provide their infants with human milk. Lactating transgender men may experience gender dysphoria and desire to initiate or reinitiate gender-affirming testosterone therapy. However, there is limited safety data regarding use of testosterone during lactation. Main Issue: A 30-year-old G2P2 transgender man with gender dysphoria sought to initiate gender-affirming testosterone therapy while lactating. Management: Subcutaneous testosterone was self-administered beginning at 13 months post-partum. We prospectively collected data on circulating testosterone concentrations in parent serum, milk, and infant serum over 5 months until the infant self-weaned. The infant was monitored for growth and development at routine pediatric outpatient appointments. Parent serum testosterone concentrations rose with the initiation of testosterone therapy, reaching therapeutic concentrations by Day 14. Milk testosterone concentrations also increased with a maximum concentration of 35.9 ng/dl when the lactating parent was on a dose of 80 mg subcutaneous testosterone cypionate weekly. The calculated milk/plasma ratio remained under 1.0 and the calculated relative infant dose remained under 1%. The infant had no observable side effects, and his serum testosterone concentrations remained undetectable throughout the study period. Conclusion: This is the first study with data regarding human milk and infant serum testosterone concentrations during the initiation of gender-affirming testosterone therapy in a lactating individual. This evidence can help families and clinicians with decisions regarding lactation and testosterone use.

Original languageEnglish (US)
Pages (from-to)339-343
Number of pages5
JournalJournal of Human Lactation
Issue number2
StatePublished - May 2022


  • breastfeeding
  • chestfeeding
  • gender dysphoria
  • human milk
  • lactation
  • testosterone
  • transgender

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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