The short answer is no — there's not much the average couple can do to affect a baby's sex.
In one study, women who ate breakfast cereal daily around the time of conception were more likely to conceive boys — but some scientists question the study's method of analysis. In addition, countless old wives' tales suggest that everything from a woman's diet to sexual position during conception can affect a baby's sex, but these theories remain unproved. Likewise, researchers have found that timing sex in relation to ovulation — such as having sex days before ovulation to conceive a boy or closer to ovulation to conceive a girl — doesn't work.
Rarely, couples face the agonizing problem of knowing they could pass a genetic trait to a child of a specific sex — usually a boy. Under those special circumstances couples may use high-tech interventions to influence the chance of conceiving a girl. For example:
- Preimplantation genetic diagnosis. With this technique — which is used in combination with in vitro fertilization — embryos are tested for specific genetic conditions and sex before they're placed in a woman's uterus.
- Sperm sorting. Various sperm-sorting techniques — which require artificial insemination or in vitro fertilization — can be used to reduce the likelihood of passing on a genetic condition, as well as select a child's sex.
Despite the feasibility of these techniques, they're rarely used when choosing a baby's sex for personal reasons is the only motivation.