The American Psychological Society annual conference: Why beauty queens give birth to girls

WOMEN WITH high testosterone levels are more likely to give birth to boys rather than girls, the conference was told. A study of barristers, solicitors and women who had been in beauty contests showed that barristers were more likely to give birth to boys and beauty contestants were more likely to have a girl.

Previous research has shown that women who do traditionally male jobs, such as managers and technical workers have higher levels of testosterone than those who do clerical jobs or are housewives.

The latest findings raise concerns that as many more women move into male-dominated occupations, their testosterone levels will rise and the ratio of boys to girls born will increase. Currently, 106 boys are born for every 100 girls.

Experts believe that the level of testosterone in women affects the acidity of the womb, which may favour male or female sperm. The sex of the foetus is determined by whether the father contributes an "X" or "Y" chromosome at the moment of conception. "The mother's testosterone level must contribute in some way to the success of the father's "X" or "Y" sperm reaching the egg and also the likelihood that a male of female fertilised egg will attach to the womb and be successful," said Jonathan Bassett, from Georgia state university, who carried out the research.It involved 58 barristers, 66 solicitors and 16 beauty contestants. Female barrister, who were seen to be in the most competitive and dominant profession, with higher levels of testosterone, were 14 per cent more likely to have a baby boy than a solicitor. They had a 60:40 chance of having a boy. In contrast beauty contestants were twice as likely to have a girl. 67: 33.

t Parents who want their daughters to have good careers should make them play netball rather than take them to art or ballet classes, according to researchers from Arizona State University. Their study of 15 and 16- year-old girls showed that those who are involved in high level competitive sports were more confident in their own ability to do any job. They felt more confident about doing traditional male occupations such as medicine, law, accountancy or engineering.