Boy or girl? Website offers test for mothers

The Auckland psychologist who developed the theory that pushy, "tough-girl" mothers have more baby boys has turned it into applied science by selling tests on the internet to predict what gender women are likely to conceive.

Valerie Grant, of Auckland University, charges $10 on The Sex Ratio website (see link below) for women who have recently conceived, or who plan to conceive, to complete a psychological test - after filling in a credit card number.

Clients are offered a list of more than 60 feelings and asked to pick the ones they experience quite often. These include feeling hopeful, vigorous, shy, sad, protected, relaxed, feeble, admired, domineering, lucky, powerful, self-satisfied, concentrating, controlling, triumphant, happy, frustrated, crushed, and alone with responsibility.

Dr Grant, who teaches at the Auckland School of Medicine, has published her work, including Maternal Dominance and the Conception of Sons, in the Journal of Medical Psychology in 1994.

In a 1998 book, Maternal Personality, Evolution and Sex Ratio, she canvassed evidence for the theory that mothers control the sex of their infants, and particularly that more dominant women were more likely to conceive boys.

A woman conceived an infant of the gender she was psychologically most suited to raise: "Her body, her personality and her behaviour are all appropriately tuned for the conception of a male or female infant".

Dr Grant's latest research, conducted on cows, suggested a female mammal's testosterone level might predispose her eggs to accept "male" sperm. It indicated that the outer layers of the egg were pre-programmed to match with sperm carrying either male Y or female X chromosomes, she said. If the sex of a child were solely down to chance, the number of boys and girls being born would even out over time, but overall 105 boys are born for every 100 girls, and at times the excess of boys is even higher.

Although women have only a tenth the testosterone men have, some scientists believe variations can influence whether a woman conceives a boy or a girl, so that she appears, like a queen bee, to dictate the sex of her offspring.

To test the theory, the Auckland researchers extracted eggs from 80 slaughtered heifers and measured the testosterone in the fluid around them.

The team, whose study has been published in the Journal of Experimental Zoology, then fertilised 34 of the eggs and compared the resulting embryos' sex with the earlier testosterone levels.

In fluid surrounding eggs that developed into male embryos, the testosterone level was on average twice as high.

But Dr Grant also noted some quite strong effects on the sex ratio of a large number of births according to the father's occupation.

"For example, airline pilots, astronauts, deep sea divers, anaesthetists, orthopaedic surgeons, truck drivers have all been shown to have more daughters," she said.

She suggested this factor could also be linked with her theory about the mother's role in determining the gender of her offspring.

"Men whose occupations require them to be totally in control tend to prefer women who are non-dominant, and these non-dominant women have daughters," she said.

"This may be part of a bigger picture that stops some characteristics going to extremes".

- NZPA