Tree-building methods developed by evolutionary biologists revealed the origins and spread of HIV. Two types arose in Africa, one from chimpanzees and one from mangabeys.
Erectile dysfunction, a major worldwide problem, is uniformly associated with aging. Biological and psychological factors contribute, but hardened arteries are a primary cause.
Variation in human skin colour with latitude is related to ultraviolet radiation needed to produce vitamin D. Deficiency can cause health issues in many people living at high latitude.
Many people, especially those living at high latitudes, suffer from vitamin D deficiency. This has insidious effects not only on bone health but also on reproduction.
Hard on the heels of birth, one woman in seven experiences nightmarish postpartum depression. Effective treatments exist, but seeking medical help without delay is crucial.
Coronavirus has been linked to increased prematurity, low birth weight, and C-section but has little effect on maternal or infant mortality. Transfer to the fetus is rare or absent
All suckled offspring digest lactose, the main milk sugar in placental mammals. Cheese making paved the way for human milk consumption after weaning; genetic mutation followed.
Human menopause is an adaptation honed by selection, not a byproduct of long lives. New facts reveal flaws in the popular "grandmother hypothesis," notably neglected grandfathers.
Pregnancy in the abdomen outside the womb is life-threatening, but not always fatal without surgery. In very rare cases, a dead fetus becomes calcified.
Romantic love is a cross-cultural human universal. Specific features of brain activation, chemical messengers, and levels of nerve growth factor accompany early-stage infatuation.
Artificial insemination, the simplest way to assist reproduction, is still widely used and even abused. Refinements include freezing semen and injection of semen into the womb.
Antibiotic resistance dramatically illustrates evolutionary change under selection. Gonorrhoea and other bacteria have become superbugs, resistant to several antibiotics.
Male/female distinctions overlap in an intersex zone. Some intersex people have atypical sets of sex chromosomes, but most have gene variants on other chromosomes.
Increasing use of “gender” as an alternative to “sex,” notably in the humanities, is inappropriate. In essence, sex is biological while gender is cultural.
Strange head shapes due to early binding arose sporadically worldwide. New reports add sites in northeast China, document local change and bolster findings for Ancient Egypt.
Chasteberry trees contain a hormone-like substance that affects reproduction in baboons and humans. Pope John XXI prescribed a conception-blocking European type for birth control.
Female orgasm is not just a functionless by-product of penis development. They are closely linked to the clitoris—part of a largely hidden complex—and may boost sperm transport.
If a fertilized egg fails to reach the womb, pregnancy begins in the wrong place, usually in an oviduct. Birth is impossible, so this life-threatening condition requires surgery.
Sperm transit through the womb and oviducts is often portrayed as a fierce contest. But contractions in the womb and oviducts also propel sperms towards the fertilization site.
In primates, dominant males usually copulate more often, but this does not guarantee paternity. Subordinate males may sire infants if their immunity genes provide a better match.
Colic — excessive crying by babies during the first 3 months — worries parents but is usually benign, mostly vanishing within 10 weeks. Effective treatment is at last in sight.
Mens’ preferences for images of narrow-waisted women purportedly evolved to maximize health and fertility. But wasp waists actually signal low fat levels and suboptimal condition.
Ritual mutilation of the external genitals of girls or women, less widespread and far more variable than male circumcision, is generally more extreme and much riskier.
Attempts to develop a reliable method for pre-selecting a baby’s sex finally succeeded. Sperms with X- or Y-chromosomes can be effectively separated using a cell flow device.
Evidence indicates that timing of coitus relative to ovulation influences a baby’s sex. But, contrary to Shettles' method, coitus near ovulation is more likely to produce girls.
This book draws on forty years of research into the roots of everything from sex cells to infant care. It examines the reproduction of humans and our primate kin to reveal the natural basis for conceiving, developing and rearing babies. Although we cannot return to raising our children as our ancestors did, there are surprising consequences of how we do things now. For instance, breastfeeding has multiple advantages for both mothers and babies, which need attention when breast-feeding is not an option, and babies may be ready for toilet training far earlier than commonly thought.
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