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Sex Selection

Family Balancing

Home Treatments Family Balancing

Many of us know someone who would desperately like to have a girl or a boy.

Perhaps a couple already has two male children, would like to have another child, but would only consider doing so if they knew they could have a girl?

When seeking assistance from a fertility center, this is referred to as “family balancing” or "gender selection".


Technology has advanced significantly in the past several years that allows individuals and couples the option of selecting the sex of their next child.

With improvements in gender selection technology, demand for gender selection has also been growing steadily.


First, a brief biology lesson:

The sex of a baby is determined by two chromosomes called sex chromosomes. Eggs from the mother carry an X chromosome, while sperm from the father carries either and X or a Y chromosome. If a Y chromosome sperm fertilizes the egg, the embryo is male (XY). If an X chromosome sperm fertilizes the egg, the embryo is female (XX). 

In natural conception, about half of all children are boys and half are girls. In order to be more certain of one sex or the other, embryos need to be created through in vitro fertilization (IVF).

A few cells are removed from the ovary, the DNA is amplified, and the 23 pairs of chromosomes are determined, including whether the embryo is an XX (girl) or XY (boy).

The preferred sex embryo is then transferred into the womb. The technology to remove cells from an embryo to determine the chromosomes is called preimplantation genetic screening (PGS).

Sex selection is done with PGS technology, which looks at all 23 pairs of chromosomes to assure that your child is chromosomally normal.


Sex selections is a viable fertility option for the following patient populations:

  • parents who already have one child or children of one sex may choose sex selection to select for a child of the opposite sex. This scenario is called family balancing
  • parents who risk transmitting an illness to a child based upon the sex of the child
  • couples who feel a need to parent a child of a certain sex for any number of reasons, including previous loss of a child or feeling better equipped to raise a child of that sex
  • the procedure for sex selection begins with conventional IVF.
  • the female partner is given hormones to increase egg production and her eggs. The eggs are then collected and combined in the laboratory with sperm.
  • after the fertilization process, rather than immediately transferring the embryos to the woman's uterus (as in conventional IVF), the embryo cells are genetically tested using preimplantation genetic screening (PGS).
  • each embryo created in the IVF cycle undergoes a cell biopsy usually at day 5 of development, and cells are observed for either the presence of two X chromosomes (indicating a female embryo) or one X and one Y chromosome (indicating a male embryo).
  • at the time of transfer, the embryos of the desired sex are implanted into the woman's uterus.
  • any remaining healthy embryos can be frozen for possible future use.


We look forward to speaking with you, and will be in touch as soon as possible!