[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"article-detail":3},{"lang":4,"article":5,"alternate":19,"related":24,"latest":33},"en",{"id":6,"slug":7,"title":8,"content":9,"summary":10,"thumbnail":11,"metaDescription":12,"metaKeywords":13,"created":14,"modified":14,"author":15,"authorEn":15,"categoryId":16,"commentCount":17,"thumbnailToContent":18},12678,"male-lactation-evolution-qsdc","Male Lactation Is Real: Why Females Nurse","\u003Cp style=\"margin:0 0 18px;\">Not necessarily. Occasionally, male mammals feed their young — including some human men.\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>The Men Who Lactated\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">In 2002, news reports described a 38-year-old Sri Lankan man who, after his wife died in childbirth, fed his two infant daughters with his own milk. In 1981, a study documented a 27-year-old man with galactorrhea related to hyperprolactinemia; his breast secretion contained lactose, alpha-lactalbumin, and lactoferrin, at concentrations within the ranges of normal human colostrum and milk.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Reports of men nursing babies go back to the nineteenth century — and, if you like, to myth. Even men without pituitary tumors can produce milk: after their nipples are repeatedly stimulated by a nursing infant, their prolactin and oxytocin levels rise, and at least some individuals can begin producing milk after a while.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">\u003Cimg src=\"\u002Fattachment\u002F20261001\u002Fa2c596e22d424c599d43d7d258e62470.webp\" alt=\"img_01.webp\">\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Other mammals do it too. Male Dayak fruit bats secrete small amounts of milk, though actual nursing by males has not been observed; their mammary development fluctuates seasonally, leaving open the possibility of auxiliary nursing. And males of many more species can lactate under stress, castration, or pituitary tumors — including the famous 2015 Indian male goat that lactated.\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>Why Did Male Nipples Survive Evolution?\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">Here is the puzzle: the genes and regulatory sequences for mammary glands exist in the genome of every normal mammal. The cells that will form the breasts are positioned before the embryo's sex is even determined. Darwin himself wondered why male nipples had not simply regressed, and cautiously suggested that there may have been a time when both sexes could nurse.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Modern biology offers an answer: carrying the breast structures without hormonal activation does not interfere with hunting, defending, or mating. There is no ecological pressure pushing males to lose them. And male nipples are not purely vestigial — they still have physiological function. Nipple stimulation causes or enhances sexual arousal in about 51.7% of men.\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>The Economics of Who Nurses\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">Females are simply more efficient at the job. During lactation, a human mother uses about 85 kcal of her food energy to produce 100 ml of milk; the infant absorbs about 70 kcal from it — a conversion of roughly 82.4%. Males can share the workload indirectly, by bringing food to the nursing female. There has never been strong selection for males to nurse directly with their bodies.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">The evolutionary logic is blunt: a male can pass on more genes by mating with more females than by nursing the offspring of one. Among mammals, males directly care for offspring in fewer than 10% of species, and far fewer actually attempt lactation. Biological traits are often redundant — kept because they cost nothing to carry.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">\u003Cimg src=\"\u002Fattachment\u002F20261001\u002F7554699a4afa4a3486fb5b6b5bc7798d.webp\" alt=\"img_02.webp\">\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>Hormones, Medicine, and the Male Breast\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">During puberty, testosterone blocks breast tissue expansion in boys. When hormones go wrong, male breasts can grow — a condition called gynecomastia that can cause distress and discrimination. Testicular failure, prolactin-secreting pituitary tumors, and cirrhosis-related hormone imbalances can enlarge male breasts and produce nipple discharge. Men recovering from long-term malnutrition may leak milk due to endocrine disruption. Men can also develop breast cancer.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Certain drugs cause nipple discharge as a side effect — anabolic steroids, for example, and antipsychotics like chlorpromazine. And because of maternal hormones crossing the placenta, newborns of either sex sometimes have nipple discharge.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">\u003Cimg src=\"\u002Fattachment\u002F20261001\u002Faebdba8ff8d64af0b462f5429cac0ad6.webp\" alt=\"img_03.webp\">\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Today, fewer than ten thousand 46, XY individuals worldwide attempt to breastfeed each year, including some transgender women. Men with benign pituitary tumors can produce more milk than the average woman. Inducing lactation with prolactin in men carries risks of other endocrine and psychological problems — though some men accept them. Transgender women nursing under medical support have accumulated reports with no indication that their usual hormones harm infants.\u003C\u002Fp>\n\u003Ch2 style=\"color:#111;font-size:21px;line-height:1.4;margin:28px 0 12px;\">\u003Cstrong>The Deeper Origin: Skin Glands, Not Fate\u003C\u002Fstrong>\u003C\u002Fh2>\n\u003Cp style=\"margin:0 0 18px;\">The mammalian breast is itself a specialized skin gland — closely related to the apocrine sweat glands, which produce the oily, protein-rich sweat of the armpits and groin. Add water, minerals, immune components, and lactose, and you essentially have milk.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">That lineage runs deep. Some fish, like discus, feed their young on parental skin mucus — a secretion that also carries immune components; both parents do it. And the platypus, an egg-laying monotreme that diverged from therian mammals over a hundred million years ago, has no nipples at all: its young lick milk from the mother's fur over the abdominal milk patch.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">The leading theory (Oftedal) traces the mammary gland to apocrine-like skin glands associated with hair follicles in ancient synapsid ancestors — secretions that first moistened parchment-shelled eggs, then became nutrient-rich milk long before true mammals appeared. Somewhere along that path, when sex-specific selection changed reproductive strategies, males stopped nursing — but the machinery never left.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">\u003Cimg src=\"\u002Fattachment\u002F20261001\u002F1c12c543d6b946a687968fc90ba94f7c.webp\" alt=\"img_04.webp\">\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">So no, nursing was never \"assigned\" to females. It was always available to both sexes; evolution just found it cheaper for males to walk away and let females carry the work. The hardware remains — and occasionally, a father uses it.\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">Want to see the glandular tissue that makes this whole story possible — the cells of a living mammal body? \u003Cstrong>WWAI\u003C\u002Fstrong> includes a \u003Cstrong>human oral epithelial cell specimen\u003C\u002Fstrong> where epithelial cells with purple nuclei are clearly visible. Just search \"WWAI\" in your app store and download it today.\u003C\u002Fp>\n\u003Cdiv class=\"dp-template-card\" style=\"border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,0.1);margin:10px 0;max-width:100%;overflow:hidden;width:100%;\">\n \u003Ca style=\"display:block;text-decoration:none;\" href=\"https:\u002F\u002Fyun-hub.chat\u002Flink\u002F?app=wwai&clickid=stellarx&dplink=specimenid%3D1039\" target=\"_blank\">\u003Cimg class=\"image_resized\" style=\"display:block;height:auto;max-width:100%;width:100%;\" src=\"\u002Fattachment\u002F20260824\u002F5ba5dd3c38404fe785f43c44423830de.png\" alt=\"5ba5dd3c38404fe785f43c44423830de\">\n  \u003Cbutton style=\"align-items:center;background-color:#1f983e;border-radius:0 0 25px 25px;border-style:none;color:#ffffff;cursor:pointer;display:flex;font-family:Times New Roman;font-size:19px;height:40px;justify-content:center;padding:0;width:100%;\">EXPLORE NOW\u003C\u002Fbutton>\u003C\u002Fa>\n\u003C\u002Fdiv>\n\u003Cp style=\"margin:0 0 18px;\">References:\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">[1] Levin RJ, Meston CM. Nipple\u002FBreast Stimulation and Sexual Arousal in Young Men and Women. J Sex Med 2006;3:450-454. https:\u002F\u002Fdoi.org\u002F10.1111\u002Fj.1743-6109.2006.00230.x\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">[2] IOL News. Sri Lankan Widower Breastfeeds His Babies (2002). https:\u002F\u002Fwww.iol.co.za\u002Fnews\u002Feish\u002Fsri-lankan-widower-breastfeeds-his-babies-96902\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">[3] Galactorrhea. StatPearls, NCBI Bookshelf. https:\u002F\u002Fwww.ncbi.nlm.nih.gov\u002Fbooks\u002FNBK537115\u002F\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">[4] Reisman T, Goldstein Z. Case Report: Induced Lactation in a Transgender Woman. Transgend Health 2018;3(1):24-26. https:\u002F\u002Fdoi.org\u002F10.1089\u002Ftrgh.2017.0044\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">[5] The Origin and Evolution of Lactation. https:\u002F\u002Fpmc.ncbi.nlm.nih.gov\u002Farticles\u002FPMC2688910\u002F\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 18px;\">All illustrations are AI-generated.\u003C\u002Fp>\n\u003Cp style=\"color:#111;margin:28px 0 8px;\">\u003Cstrong>Related reading\u003C\u002Fstrong>\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 20px;\">\u003Ca style=\"color:#111;text-decoration:none;\" href=\"https:\u002F\u002Fstellarx.tech\u002Farticle\u002Ff4b1c3-ai-animation-evolution-debate\">\u003Cimg class=\"image_resized\" style=\"border-radius:8px;display:block;height:auto;margin-bottom:6px;max-width:520px;width:100%;\" src=\"https:\u002F\u002Fcdn.banyunjuhe.com\u002Fattachment\u002F20260830\u002F8689d819a3d24107b610eb4e3cf0588d.png\" alt=\"Nature’s Living Flamethrower: When AI Animation Ignites Evol…\">\u003C\u002Fa>\u003Cbr>\u003Ca style=\"color:#0b6cb0;text-decoration:none;\" href=\"https:\u002F\u002Fstellarx.tech\u002Farticle\u002Ff4b1c3-ai-animation-evolution-debate\">\u003Cstrong>Nature’s Living Flamethrower: When AI Animation Ignites Evol…\u003C\u002Fstrong>\u003C\u002Fa>\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 20px;\">\u003Ca style=\"color:#111;text-decoration:none;\" href=\"https:\u002F\u002Fstellarx.tech\u002Farticle\u002Ftextbook-diet-nutrition\">\u003Cimg class=\"image_resized\" style=\"border-radius:8px;display:block;height:auto;margin-bottom:6px;max-width:520px;width:100%;\" src=\"https:\u002F\u002Fcdn.banyunjuhe.com\u002Fattachment\u002F20260927\u002F1839a53baff5458bb03e5ea23cc59cca.png\" alt=\"Textbook Diet: 7 Nutrition Rules From a 670K-View Thread — W…\">\u003C\u002Fa>\u003Cbr>\u003Ca style=\"color:#0b6cb0;text-decoration:none;\" href=\"https:\u002F\u002Fstellarx.tech\u002Farticle\u002Ftextbook-diet-nutrition\">\u003Cstrong>Textbook Diet: 7 Nutrition Rules From a 670K-View Thread — W…\u003C\u002Fstrong>\u003C\u002Fa>\u003C\u002Fp>\n\u003Cp style=\"margin:0 0 20px;\">\u003Ca style=\"color:#111;text-decoration:none;\" href=\"https:\u002F\u002Fstellarx.tech\u002Farticle\u002Fflu-vaccine-immunity\">\u003Cimg class=\"image_resized\" style=\"border-radius:8px;display:block;height:auto;margin-bottom:6px;max-width:520px;width:100%;\" src=\"https:\u002F\u002Fcdn.banyunjuhe.com\u002Fattachment\u002F20260927\u002Fa31b409e60e04e7dafe25f720e607e26.png\" alt=\"Flu Season 2026: Why the Flu Shot Is Worth It — H3N2, Antige…\">\u003C\u002Fa>\u003Cbr>\u003Ca style=\"color:#0b6cb0;text-decoration:none;\" href=\"https:\u002F\u002Fstellarx.tech\u002Farticle\u002Fflu-vaccine-immunity\">\u003Cstrong>Flu Season 2026: Why the Flu Shot Is Worth It — H3N2, Antige…\u003C\u002Fstrong>\u003C\u002Fa>\u003C\u002Fp>","","\u002Fattachment\u002F20261001\u002Fd5100f3325084648a297395442dcb54c.webp","Men can lactate — a widower breastfed his daughters, and nipple stimulation raises prolactin. Yet evolution kept nursing mostly female. Here is why","Men can lactate — a widower breastfed his daughters, and nipple stimulation raises prolactin. Yet evolution kept nursing mostly female. Here is why.","2026-10-01 16:28:11","Science Guide Wwai",77,0,false,{"id":20,"slug":21,"title":22,"lang":23},12665,"hong-kong-milk-tea-vs-bubble-tea","港式奶茶為什麼這麼苦？「絲襪奶茶」和珍珠奶茶到底有什麼不同？","zh",{"prev":25,"next":29},{"id":26,"slug":27,"title":28,"categoryId":16},12679,"methylmercury-baby-label-mvwp","Mercury in 'Baby Cod': A Toddler's Label Trap",{"id":30,"slug":31,"title":32,"categoryId":16},12677,"protein-intake-rule-origins-ckpm","Where the 1.6–2.2 g\u002Fkg Protein Rule Comes From",[34,39,44,49],{"id":35,"slug":36,"title":37,"thumbnail":38,"categoryId":16},12685,"food-adulteration-history-bwxa","Ancient Food Was Never Pure: Urine, Lye, and Fake Fish","\u002Fattachment\u002F20261001\u002F03bbfa285e6545d6b3144a2fb3e790f9.webp",{"id":40,"slug":41,"title":42,"thumbnail":43,"categoryId":16},12684,"glowing-algae-story-zptc","When Lockdown Laziness Grew Glowing Algae","\u002Fattachment\u002F20261001\u002F2915a99ca6dd44bb99d4131bc2f639b5.webp",{"id":45,"slug":46,"title":47,"thumbnail":48,"categoryId":16},12683,"alpha-gal-syndrome-gmht","Why a Tick Bite Can Make You Allergic to Red Meat","\u002Fattachment\u002F20261001\u002Faa24a6f7e36b4b2fb5b8a0f6c3bfd1d8.webp",{"id":50,"slug":51,"title":52,"thumbnail":53,"categoryId":16},12682,"centipede-leg-count-comparison-lqzv","Who Has More Legs: House Centipede or Centipede?","\u002Fattachment\u002F20261001\u002Fb139d5c1b20648f39e4eca5fb29ac3f2.webp"]