We Are Our Brains: From the Womb to Alzheimer’s, by Dick Swaab, Allen Lane, RRP£20/$28
The human brain seems to be fertile territory for Dutch authors. The psychologist Douwe Draaisma has built an international reputation on his books about memory, and neurobiology professor Dick Swaab has written a blockbuster about the brain – translated into English after selling more than 100,000 copies in the Netherlands.
We Are Our Brains takes an extraordinarily broad sweep through the past and present of neuroscience, moving as the book’s subtitle says from the womb to Alzheimer’s. While all the main scientific, medical and ethical issues are covered, the structure is somewhat fragmented – perhaps reflecting the book’s origins in a series of newspaper columns answering readers’ questions in NRC Handelsblad – and the quality is patchy.
But the best bits bring out remarkable insights from Prof Swaab’s 40-plus years in clinical neurobiology, spiced with some provocative political ideas. He is most interesting about the two ends of life: how an individual’s genetic inheritance and biochemical environment in the womb determine almost everything about their psychology before birth; and how to die with dignity.
Sexual orientation is absolutely fixed in the womb, insists Prof Swaab, who has carried out considerable research on the biological origins of homosexuality. Indeed his work played a significant part in changing a scientific view, held widely until the 1980s, that gender identity was determined largely by social influences during childhood.
Precisely what combinations of genes, hormones and other chemicals induce future homosexuality, bisexuality or heterosexuality in the embryonic brain – and how they work – remains mysterious, though Prof Swaab offers some intriguing clues.
For instance, the more older brothers a boy has, the greater chance that he will be gay. “This is due to a mother’s immune response to male substances produced by boy babies in the womb, a response that becomes stronger with each pregnancy,” he tells us. And women suffering from stress during pregnancy are more likely to give birth to homosexual children because their raised levels of the stress hormone cortisol affect the production of foetal sex hormones, which in turn influence the developing brain.
Whatever the causes, Prof Swaab is adamant that events after birth do not affect sexual orientation. Children brought up by lesbians are not more likely to be gay; homosexuality should never be regarded as a “lifestyle choice”; and attempts by some religious groups to “cure” people of homosexuality are doomed.
At the other end of life, Prof Swaab offers some fascinating observations about Alzheimer’s disease, another of his personal research interests. He asks us to see patients’ progress to dementia as a rewinding of a film of their life back to the start, “culminating in a state of complete dependence that leaves them curled up in a foetal position, demented and effectively brain-dead”. He adds that, if you put a finger into the mouth of someone with advanced Alzheimer’s, “he will show a sucking reflex, having at that point fully regressed to the condition of a newborn baby”.
The author is one of the medical campaigners who are partly responsible for the liberal Dutch laws on assisted dying and euthanasia. Indeed he now wants the Netherlands to go further, so that old people can receive medical help to die if they “feel their time has come” but are not terminally ill. He cites an online petition to have the issue discussed in the Dutch parliament that gathered the 40,000 signatures required within four days. “Given the enormous public interest, it’s amazing how much abuse we received: our group was dubbed ‘the death squad’,” Prof Swaab writes with a faux naïveté that creeps occasionally into the book.
In 2002 he responded to the fierce debate about introducing a civic integration course for foreigners (with its xenophobic undertones) by lobbying half-seriously for everyone in the Netherlands to take a civic “disintegration” course to prepare for the last phase of life. Of course that did not fly but Prof Swaab argues sensibly for an “exit course” to be set up for trainee doctors and the wider public. It would cover all the issues associated with dying, such as pain relief, palliative sedation and terminal dehydration, for which most people are completely unprepared.
Prof Swaab knows exactly what should happen to his body when the time comes. His brain should join 3,000 others in the Netherlands Brain Bank, an international research resource that he set up in 1985. His other organs can used for transplants if anyone wants such well-worn body parts. Doctors are welcome to perform a postmortem if they think that would be useful – and “I don’t care what happens to the rest of me”.
The writer is the FT’s science editor