Gender selection is the process of determining the genetic sex, male or female, of each embryo created through in vitro fertilization (IVF). Genetic sex of an embryo depends on whether the egg is fertilized with a spermatozoon (sperm) containing X or Y chromosome. However, selecting the baby's gender through the use of IVF in fertile couples for non-medical reasons is a controversial issue.

For whom is gender selection appropriate?

Couples may select to have a baby with a particular gender -boy or girl- for personal or medical reasons

• For couples willing to have a baby of a particular gender
• For couples willing to avoid a sex-linked genetic disease in their newborn

Techniques preferred for gender selection

1. Preimplantation Genetic Diagnosis (PGD); With the development of Polymerase Chain Reaction (PCR) technologies, today, by obtaining specific DNA fragments from a single cell, both genetic testing and sex determination of the embryo can be performed before embryo transfer. It is an expensive technique.Couples wishing to select the sex of their baby are required to undergo the same protocols and treatments as in normal in vitro fertilization cycle. That is, a woman’s eggs are retrieved and fertilized with her partner’s sperm to create embryos. In order to obtain embryonic genetic material for analysis, a biopsy is required. Embryo biopsy involves the removal of five or seven trophectorm cells from blastocyst stage embryo for testing gene mutations or aneuploidy (chromosome abnormalities) without damaging the embryo. PGD also also allows the embryologist to determine the sex of each embryo tested. The aneuploidy embryos or embryos with gene mutations are discarded and the healthy embryo(s) with the desired sex is/are selected for embryo transfer. As the analysis usually takes a few days, the most common practice is to freeze the healthy embryos free from genetic disorders and chromosome abnormalities and transfer them to the uterus in the next cycle.Preimplantation genetic test also allows the diagnosis of single gene diseases such as Mediterranean anemia and cystic fibrosis.
2. Preimplantation sperm separation via flow cytometric sorting
   Flow cytometric sorting is used to separate sperm based on sex chromosome content. Human sperm sorted by flow cytometry can increase the likelihood that a child so conceived will be of a particular sex. This provides a preconception reproductive option for parents wishing to reduce sex-linked and sex-limited disease risk for their future children. After sorting for X-bearing and Y-bearing sperm, the sorted sperms are used for IUI and IVF/ICSI. Considering sex of babies born through IVF/ICSI fertilized embryos, the success rate is 93.5% in females and 82 % in males.
3. Swim-up method:
   It is a technique developed sorting sperm with the belief that Y-bearing sperms move faster. The success rate is almost similar to flow cytometry.
4. Scheduled sexual intercourse and diet:
   The two most common methods, but neither of them are effective.