Sex Selection
Last reviewed 2026-10-27
Sex selection means influencing or choosing whether a child will be male or female. Only one method gives a definite answer: testing an embryo's chromosomes during IVF and transferring an embryo of the chosen sex. Everything else — sorting sperm, timing, diet — shifts the odds at most. Done for a medical reason, to avoid a sex-linked disease, it is lawful almost everywhere. Done for preference, it is prohibited in most countries that regulate fertility treatment.
Medical and non-medical: the distinction every law turns on
Essentially every legal instrument in this field draws the same line, and understanding it explains the whole regulatory map.
| Medical sex selection | Non-medical sex selection | |
|---|---|---|
| Purpose | Avoiding a serious disease that affects one sex — haemophilia and Duchenne muscular dystrophy are the classic examples | Parental preference, including family balancing |
| Legal status | Permitted in most regulated jurisdictions, usually subject to approval | Prohibited in the UK, Canada, Australia, Ireland, India and most of the EU |
| Who decides | A clinical indication, often with a named condition on an approved list | The patient — which is precisely what the prohibitions object to |
This is why a clinic can lawfully advertise “gender selection” in one country and face criminal liability for the same procedure in another, and why the UK statute reads the way it does: it bars the practice in general and then carves out the medical case.
The methods, ranked by whether they work
- Embryo testing during IVF (PGT-A). The only method that gives an answer rather than a tilt. The sex chromosomes are read from a day-5 embryo biopsy. See how it works.
- Flow cytometric sperm sorting. A real mechanism — X-bearing sperm carry slightly more DNA — but the published enrichment figures come largely from the programmes selling it.
- Albumin gradient (Ericsson method). Decades old, cheap, and not supported by consistent evidence.
- Timing, diet, pH, home kits. Tested and not supported. These perform at chance.
The detail on each, including what happened to MicroSort, is on gender selection without IVF.
Why this is regulated at all
The objections are not interchangeable, and it is worth separating them because different countries legislate against different ones.
- Population sex ratios. The strongest evidence-based objection, and the reason India legislates criminally. Where a strong son preference meets accessible technology, birth ratios distort measurably and at scale. This argument has force in some societies and very little in others.
- Treating a child's sex as a specification. An objection about the parent–child relationship rather than about populations. It is a moral argument and it is held sincerely on both sides.
- Discarding healthy embryos. Weight here depends entirely on what you think an embryo is.
- Medicalising a preference. Exposing a woman to stimulation, egg collection and anaesthesia for a non-medical goal. This is why some clinics in permissive countries still decline.
Against them sits the case that the choice is private, affects no one else, and that the alternative is not no sex selection but sex selection for those who can afford to fly. Australia's own regulator found the majority of public submissions favoured a permissive approach when it reviewed the question in 2017, and kept the prohibition anyway. This is a live argument, not a settled one, and a site that pretended otherwise would be selling you something.
Family balancing: the term that does the work
Much of the industry operates under the phrase family balancing — selecting for the sex you do not already have. It is a narrower practice than sex selection in general and it is where permissive clinics in regulated countries tend to draw their own line, even where the law does not require them to. It has its own page: family balancing.
What is sex selection?
Choosing or influencing whether a child will be male or female. The only reliable method is testing embryos during IVF and transferring one of the chosen sex; sperm sorting shifts the odds at best.
Is sex selection the same as gender selection?
They are used interchangeably in clinic marketing and in searches. Strictly, what is selected is the sex chromosomes of an embryo, not gender.
When is sex selection allowed?
Almost everywhere when it is done to avoid a serious sex-linked disease, usually subject to approval. For parental preference it is prohibited in most countries that regulate fertility treatment, with the United States the main exception among English-speaking countries.
Why is non-medical sex selection banned in so many countries?
The arguments cited are distortion of population sex ratios, objections to treating a child's sex as a chosen attribute, the discarding of healthy embryos, and exposing a patient to medical risk for a non-medical purpose. Which argument carries a given law varies by country.
Countries Where Gender Selection Is Legal
Where IVF gender selection is legal, country by country, with the legal instrument for each — and which rows we ver…
Gender Selection Without IVF
Gender selection without IVF: sperm sorting, the Ericsson method, IUI, timing and home kits against the published e…
Family Balancing
Family balancing is selecting the sex you do not already have. What clinics mean by it, who qualifies, and where th…