Androgen Effects on the Reproductive Neuroendocrine Axis, 2025 Version

Inclusion Criteria: Transgender/Non-binary Group, Initiating Testosterone Group

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Aged 18-35
* Plan to initiate testosterone therapy
* History of regular menstrual cycles (every 24-35 days) at baseline, before beginning TRT

Inclusion Criteria: Cisgender Female Group

* Provision of signed and dated informed consent form
* Stated willingness to comply with all study procedures and availability for the duration of the study
* Aged 18-35
* Having regular menstrual cycles (every 24-35 days)

Exclusion Criteria: All

* Pregnant
* Incarcerated
* Known cognitive impairment or institutionalized
* Hemoglobin less than 11 gm/dl at screening evaluation
* Weight less than 110 pounds
* BMI \<18 or \>35
* Current endocrine disease- including untreated thyroid abnormalities, pituitary or adrenal disease, polycystic ovary syndrome, or androgen producing tumor
* Current or recent pregnancy within two months of study enrollment
* Current or recent breast feeding within two months of study enrollment
* Diabetes, or renal, liver, or heart disease
* History of oophorectomy or hysterectomy
* History of radiation or surgery involving brain structures and/or pelvis/pelvic organs
* Currently taking any medications that may affect their reproductive hormones, such as contraceptive medications, androgens, estrogens, progestins, gonadotropin-releasing hormone (GnRH) antagonists, insulinomimetics, and metformin.
* History of prior testosterone therapy