Women who are stressed while trying to conceive are more likely to have girls, research suggests.
According to the new study , women who were under pressure at home, work or in their love lives in the weeks or months before getting pregnant had higher chances of giving birth to a girl rather than a son.
The finding, by Oxford University and U.S. researchers, means the economic downturn could see more women give birth to daughters. The study follows others that have shown the number of baby boys goes down following major upheavals.
For instance, in the months after the 9/11 terrorist attacks, the number of boys born in New York plunged, while the economic chaos that followed the collapse of the Berlin Wall saw far fewer boys born than expected in the former East Germany in 1991.
But the latest study is the first to link the phenomenon to the stresses and strains of everyday life and to rising levels of stress hormones.
Some 338 women from around the UK who were trying to get pregnant kept diaries about their lives and sex lives and filled in questionnaires about how stressed they felt. Levels of stress hormones including cortisol were measured in the months before pregnancy.
Of the babies born, 58 were boys and 72 were girls. Normally, in Britain 105 boys are born for every 100 girls.
When all the women were put together – stressed and calm – the result could have been due to chance.
But among the 50 per cent of the women who had the highest amounts of cortisol before pregnancy, the sex ratio was clearly skewed towards girls, the American Society for Reproductive Medicine’s annual conference heard.
A clinical embryologist, Dr. Ewache E.A. says that, “women have little or no contribution to the determination of the sex of a child. The X and Y chromosomes of the male are responsible for conception. The component of the male gamete that fuses with the egg determines the sex of a child”.
Ewache explains further: “When the X chromosome of the male fuses with the X chromosome of the female, a girl is produced while a male is produced when the Y chromosome fuses with an X chromosome’’.
The Abuja-based medical practitioner, who also owns a medical and fertility centre, notes, that there is no medical evidence to support the claim that when women are under pressure there is a possibility of having a female child. “The only proven determination of a baby’s gender is pre-implantation or genetic diagnosis which is done through Invitro Fertilisation (IVF)”, he said.
In this case, couples can choose the sex of the baby they want. This can be achieved by two theories: selection procedure or media method.
He pointed out that another theory that may determine the gender of a baby is when a man abstains from his wife for some days.
According to Ewache, it is believed that during that period the sperm is thick and the Y chromosomes travel faster which is likely to produce a male child. If the sperm is watery, the X chromosome moves faster which could result in conceiving a female child.
“Apart from these theories that had been postulated, stress cannot in anyway determine the sex of a child. Moreover, this may just be a form of experiment with no substantiated medical evidence or scientific proof,” he noted.
However, a mother of five girls, Mrs Habibat Lawal disagrees with the notion that working under pressure could lead to conceiving a female child.
Citing her case as an example, she says, “I have been married for over 10 years and I am a full house wife. I have never worked in my life because we are very comfortable. All my children are girls. If working under pressure is the reason for having girls, then that theory is wrong because I don’t work at all, not to talk of working under pressure”.
She also says, “Like we were taught in school those days, the male is solely responsible for the determination of the sex of a child because it is what the sperm produces that the woman conceives”.
Dr Allan Pacey, a Sheffield University fertility expert, described the notion as ‘intriguing’ but said that stress may not necessarily be behind conceiving girls but nutrition or simple biology may play a part.
Past research has shown that dominant women are more likely to have sons –perhaps because their higher levels of testosterone ‘prime’ their eggs to make fertilisation with male sperm more likely.