PINK OR BLUE? Can you try for a boy or girl?
Is it really possible to conceive a boy or girl by choosing the time of conception according to your cycle?
There are plenty of old wives’ tales about how to conceive the gender of your choice. Have you heard about having sex under a full moon to conceive a girl, or a quarter moon for a boy? Try the missionary style for a girl or standing up for a boy, or facing a certain way (placing the head of the bed to the north) for a boy. To get a girl, eat chocolate and for a boy, you must eat red meat. Yes, really. However, it’s best to take all these bits of lore with a large pinch of salt. In reality, whichever method you opt for, you have about a 50 percent chance of having a baby of either sex.
WHAT DETERMINES A BABY’S SEX?
It’s actually the sperm that determine the sex of your baby. The egg a woman ovulates carries an X chromosome, while sperm carry either an X or a Y chromosome. If the sperm with an X chromosome fertilises the egg (XX), the embryo will develop into a girl baby, while an XY embryo, fertilised by sperm with a Y chromosome, will develop into a boy baby.
IS TIMING EVERYTHING?
There is a widely-held belief that boy sperm are faster, but more fragile, than girl sperm, which are supposedly slower, but more resilient. In fact, the Shettles Method works on this assumption and advocates using timed intercourse on specific days of your cycle to increase your chances of having either a boy or a girl. The basis of the method is that Y chromosome sperm move faster, but don’t live as long as sperm carrying X chromosomes, so you should have sex as close as possible to ovulation to conceive a boy, whereas for a girl, you should have sex two to four days before you ovulate. Not everyone’s cycle is standard though, so you’d need to use an ovulation predictor kit or chart your basal body temperature to know for sure when you’re ovulating. Another method that supposedly works on the timing of intercourse is the Whelan Method, which directly contradicts the Shettles Method. The theory behind this method is that biochemical changes that may favour boyproducing sperm happen earlier in your cycle, so if you want a boy, you should have sex four to six days before your basal body temperature goes up. If you want a girl, have sex two to three days before you ovulate. You’d need to chart your basal body temperature every day to figure out when you’re ovulating. However, there’s no scientific evidence that either of these methods work. They’ve all got about a 50 percent chance, comments reproductive medicine specialist Dr Yossi Unterslak of Vitalab. The same is true of sperm washing, which purports to separate male and female sperm, “and that as well is really a 50/50 chance, but there’s really no good science to this,” he adds.
GETTING TECHNICAL
It is possible to select the sex of your baby and leave nothing to chance by using the magic of science. In-vitro fertilisation (IVF) utilises testing that can indicate sex. However, the law in South Africa is very clear: choosing the sex of your baby for social (not medical) reasons is illegal. Specifically, the law states that: “Pre-implantation and prenatal testing for selecting the sex of a child is prohibited, except in the case of a serious sex-linked or sex- limited genetic condition.” There are situations where there is a valid medical reason for selecting a particular sex. “Because specific diseases are linked to gender, in those cases – to eliminate the disease or eliminate the risk of having a child with that disease – you are able to select sex,” says Dr Unterslak. There are a number of prenatal tests that can be used. PGS (pre-implantation genetic screening) is a screening test that looks at the embryo’s chromosomes for deletions or additions. This detects chromosomally abnormal embryos that would result in IVF failure, miscarriage or babies born with Down syndrome, Edwards syndrome (Trisomy 18), Turner syndrome and some other genetic conditions. Pre-implantation genetic diagnosis (PGD) is specific to certain genetic diseases. This would be utilised by parents who are carriers of a serious genetic disease and who want to avoid a serious inheritable genetic disease, some of which are sex-linked and affect mainly males, such as cystic fibrosis, Duchenne muscular dystrophy and other singlegene disorders.