Breast development extension adrenocorticotropic hormone (ACTH)), and thyroid hormones such as thyroxine (and by extension thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH)) also play permissive but less well-understood/poorly-characterized roles in breast development during both puberty and pregnancy, and are required for full functional development. Leptin has also been found to be an important factor in mammary gland development, and has been found to promote mammary epithelial cell proliferation. In contrast to the female-associated sex hormones, estrogen and progesterone, the male-associated sex hormones, the androgens, such as testosterone and dihydrotestosterone (DHT), powerfully suppress the action of estrogen in the breasts. At least one
Human male sexuality Human male sexuality Human male sexuality covers physiological, psychological, social, cultural, and political aspects of the human male sexual response and related phenomena. It encompasses a broad range of topics involving male sexual desires and behavior that have also been addressed by ethics, morality, and religion. There are a number of factors that influence male sexuality and sexual behaviour, including expected parental investment, and paternal presence during development. Elizabeth Cashdan proposed that mate strategies among both genders differ depending on how much parental investment is expected of the male, and provided research support for her hypotheses. When men expect to