Individuals who want to choose the sex of their child have historically turned to unreliable methods in an attempt to achieve this goal. Popular but unproven approaches typically rely on the theory that Y bearing sperm swims faster or that X bearing sperm is hardier.
Methods with No Supporting Evidence
The Whelan and Shettles methods are implemented by timing intercourse to occur on specific days around a woman’s ovulation cycle. Proponents of these techniques claim that sexual position is also important for success. There is little evidence that these sex selection techniques affect the usual 50/50 sex ratio.
The Ericsson method involves collecting sperm from the male partner and sorting it in a lab environment. The sperm is sorted by measuring the speed with which it swims through multiple layers of albumin (a blood component). There is no large scale, controlled medical trials involving the Ericsson method. Samples tested using this selection technique have consistently been shown to have a 1:1 ratio of X and Y carrying sperm.
Microsort is advertised as aiding gender selection by sorting sperm in a centrifuge to separate it into X and Y components based on minute differences in molecular weight. An FDA trial of this method was discontinued prematurely and is not approved for use in general fertility treatment. Initial results for this technique have not yet been replicated in large, multi-center trials.
Method Proven Successful
Currently, preimplantation genetic diagnosis (PGT-A) is the only proven method of sex selection. This approach involves safely removing cells from a 5 day old embryo during an In Vitro Fertilization cycle. PGT-A sex selection is over 99% accurate.