Natural methods — Timing intercourse around ovulation, sexual positions, diet, or similar techniques are often promoted for “boy or girl” selection, but there is no reliable scientific evidence that these methods can determine the baby's sex.
IVF with embryo testing (PGT) — During in-vitro fertilization, embryos can be genetically tested before transfer. This can identify the sex chromosomes, making sex selection highly reliable. However, IVF is expensive, invasive, and whether non-medical sex selection is permitted depends on the country and clinic.
Sperm sorting — Techniques can enrich sperm carrying either X or Y chromosomes, but they are less reliable than embryo testing and availability varies.
Importantly, the father's sperm determines whether the embryo receives an X or Y chromosome: X sperm + X egg generally produces XX (female), while Y sperm + X egg generally produces XY (male).
