Bossy women have boys

Tim Utton12 April 2012

They have broken through the glass ceiling in the world of work. Now it seems that tough, confident women are shattering preconceptions in the area of childbirth.

Research has revealed that forceful mothers-to-be are far more likely to give birth to sons than daughters.

Assertive women have an 80 per cent chance of having a son because they have higher levels of testosterone, the studies found.

This may make it easier for women in high-powered executive jobs to conceive a male embryo - while quieter, more easy-going types are more likely to have girls.

These findings challenge the traditional view that the father determines the baby's sex, through the chromosomes in his sperm.

Dr Valerie Grant, a psychologist based at Auckland University, New Zealand, said: 'Dominant women have more testosterone and that's why they produce more sons.

'People everywhere have it ingrained in them that the father's big contribution to the reproductive process is the sex of the offspring.

'But I think the evidence that the male has anything to do with it is very flimsy.' Many animals can control the sex of their offspring, said Dr Grant, producing young of the sex that will do best under the prevailing conditions.

To try to predict the sex of a woman's baby, Dr Grant invented a personality test which gauged the personalities of mothers-to-be.

The test asked women to describe their personalities from a choice of 64 listed adjectives such as proud, free, bored, awed and arrogant.

Sprinkled among them were 13 words linked with high dominance, and women were scored on how many of these they pick to describe themselves.

An average score was to include three such words - such as strong, controlling, powerful, dignified, masterful, excited, serious, lucky, alert.

But women who picked eight or more of the 13 dominant words indicated that in 80 per cent of cases, a boy was on the way.

Those words which indicated a girl included: shy, troubled, insecure, inhibited, protected, distressed, sheltered, defeated.

Dr Grant believes the huge increase in male births after the two world wars was caused by the more dominant positions in society taken by women while the men were away - which led to a raising of their testosterone levels.

Her study, published in the journal Biological Psychology, confirmed that women who score highly on the dominance test also have highest levels of the male hormone.

She believes that high testosterone levels 'prime' the woman's eggs to be receptive to fertilisation by sperm bearing a 'male' Y-chromosome.

This may have evolved in humans to allow women to have babies of the sex that they are best suited to nurture.

Herself a mother of three sons, Dr Grant developed the theory after she found she was able correctly to predict the sex of babies born to her friends and colleagues, based on what she knew about the mother. Her early guesses were right 33 times out of 36.

A study at Liverpool University has backed up her theory, claiming in July that couples who have comparatively long ring fingers have a higher chance of having a boy, as this indicates higher than average testosterone levels.

Other researchers have suggested that women with active sex lives are more likely to have a son.

The publication of Dr Grant's findings comes days after it was revealed that dozens of British couples are trying to choose the sex of their baby using a controversial fertility treatment costing up to £15,000.

One couple, who already had two healthy boys, conceived the girl they longed for after using the 'sperm sorting' technique in the United States.

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