If you want to welcome a bundle of pink, can tweaking your diet in other ways boost the chances?
The recently reported research did find moms-to-be who favored breakfast cereal and a potassium-rich diet delivered more boys than moms who skipped breakfast and took in fewer calories. But experts contacted by WebMD caution that the study simply found an association. There is no cause-and-effect proof that what you eat sways the outcome of conception, gender-wise, they say.
But that doesn't stop people -- everyone from your Grandma to the stranger in your gynecologist's waiting room -- from suggesting a variety of approaches to influence the sex of your unborn child. The list goes far beyond breakfast cereal and potassium-rich foods like bananas.
We asked reproductive experts, obstetricians, and those who promote some of the sex-selection methods to explain and weigh in on the options.
Breakfast Cereal and Sex Selection
In a study published in the Proceedings of the Royal Society B, 740 newly pregnant British women recalled what they ate the year before conception. Those who ate breakfast cereals and potassium-rich foods and consumed more total calories daily delivered more boys compared to those who skipped breakfast and ate fewer total calories.
It's not certain whether the calories or the nutrients makes the difference, the researcher says, although the association is one that is seen in other animals, with well-fed mothers giving birth to males and less well-fed mothers delivering females.
Among the evolutionary theories as to why girls or boys are conceived is that parents in good condition favor male offspring or that the availability of resources and other factors affects the sex ratio. One study, for instance, shows that underfed hamsters tend to deliver females while hamsters not restricted on diet do not.
Low-Tech Methods of Sex Selection
Methods to up the odds of conceiving a boy or a girl are plentiful. If you search the web for "gender selection" you'll get multiple hits to articles, a book called How to Choose the Sex of Your Baby, and several commercial web sites selling gender-preference kits. Many of these approaches suggest one or more of the following techniques:
- Timing intercourse closer to ovulation for a boy, further away for a girl. The reasoning is that the "girl" sperm (with X chromosomes) are hardier and the "boy" sperm (Y chromosomes) are more fragile, so having intercourse as close as possible to ovulation will give those Y chromosomes that determine maleness a fighting chance of meeting the egg.
- Making the vaginal environment more hospitable to "girl" or "boy" sperm. Some say this can be done by douching with water and vinegar to make the environment more acidic and girl-friendly and by douching with water and baking soda to make the environment more alkaline and boy-friendly.
- Adopting various positions during intercourse. For instance, the missionary position is recommended for producing girls; rear-entry for boys.
But Steven Ory, MD, a reproductive endocrinologist in the Ft. Lauderdale, Fla., area and past president of the American Society of Reproductive Medicine, disagrees. "There really is no old-fashioned technique that can influence sex selection," he tells WebMD.
"Nothing is proven," agrees Richard P. Frieder, MD, a staff gynecologist at Santa Monica-UCLA & Orthopaedic Hospital in Santa Monica, Calif. And finding an association between dietary habits or intercourse timing or other approaches and having more girl or boy babies is different than finding a cause and effect, he points out.
"To propose there really is a cause and effect is really on the fringe," he says of the old-fashioned sex- selection techniques.
His patients who are hoping for one sex over another always ask if there is anything simple they can do to boost the odds of conceiving a child of the preferred sex. "I tell them it's 50-50. The reality is there is nothing you can do that really matters."
"You have a 50-50 probability of a girl or a boy," Ory says. If a couple is trying interventions such as dietary changes or different positions or intercourse timing, he says, "there is a tendency to attribute what you did to getting results [you wanted]. And people tell their friends. In medicine, we call them anecdotes."
Proponents of Low-Tech Methods
Combining techniques can give better results, says M. Jericho Banks, PhD, a partner and owner of Gen Select, a preconception sex selection method sold online.
By adjusting the body chemistry to be more acidic or more alkaline, he says, couples can boost the chances of conceiving their preferred sex.
For instance, his company advises those who want a girl to avoid salt and eat a lot of protein. "It falls in line with the recent study," he says.
"A lot can help," Banks contends. Making the vaginal environment and body chemistry "more hospitable" to one or the other type of sperm can influence conception, he says.
Hazards of Sex Selection?
The dietary changes seem harmless, according to Frieder. But nutritionists caution women not to skimp on calories or nutrients in the hopes of conceiving a girl, based on the recent study.
But the method that suggests having intercourse before or after ovulation, depending on whether a boy or a girl is preferred, may actually reduce the chances of getting pregnant at all, Frieder says, if couples miscalculate their ovulation.
In general, the overall chance of getting pregnant each month is fairly low, he says. "There is a 20% chance of getting pregnant in one menstrual cycle if the sex is at the perfect ovulation time," Frieder says. If the intercourse occurs earlier or later, the odds of getting pregnant could decline, he says.
As for the suggestion to douche, Frieder advises not. "They could be caustic to the sperm."
But in general, most of the low-tech methods to influence a baby's sex seem harmless, even if they don't work, Frieder says. "It gives couples something to do while they are waiting to get pregnant."
Allyson A. Gonzalez, MD, another gynecologist at Santa Monica-UCLA & Orthopaedic Hospital, agrees. Old wives' tales may deserve respect, she says, even if they aren't backed by scientific proof. "Old wives tales don't come from nowhere," she says. If a method won't harm parents-to-be or the unborn baby, she says, she doesn't discourage it. But she cautions couples not to count on any of the methods working.