Is Hirsutism Hereditary? What Runs in Families and What Doesn’t

Short answer: Partly. The most common causes of hirsutism, PMOS (formerly PCOS) and so-called idiopathic hirsutism, clearly run in families, and twin studies suggest around 70% of the risk of PMOS is genetic. One less common cause, non-classic congenital adrenal hyperplasia (NCAH), is directly inherited. Other causes, like medications and hormone-producing tumors, are almost never passed down.

“Is it hereditary?” was one of the questions readers asked in our survey of 269 women^[1]. It is a fair question. Many women notice that their mother, sister or aunt also deals with chin hair or a darker upper lip, and many worry about their daughters. The honest answer is that genes play a real role, but “hereditary” does not mean “inevitable,” and different causes of hirsutism are inherited in very different ways.

Your genes set how much hair is “normal” for you

Before looking at medical conditions, it helps to know that the baseline amount of body and facial hair varies a lot between families and ethnic groups. A large consensus statement from the Androgen Excess and PCOS Society notes that terminal body hair growth has substantial racial and ethnic variability^[2]. That is why doctors do not use a single cutoff on the Ferriman-Gallwey score for everyone.

Population studied	Score at which hair counts as “above normal” (95th percentile)
ck and White women	8 or higher
rranean and Middle Eastern women (Spain, Italy, Turkey, Iran)	About 8-11, depending on the study
inese women in China	2 or higher
nd Chinese women in Thailand	3 or higher

These numbers come from studies of unselected women summarized in the consensus statement^[2]. The point is not the exact number. It is that a woman of Mediterranean or Middle Eastern descent may have more hair than a woman of East Asian descent, and both can be completely healthy. If your whole family is on the hairier side, part of what you see may simply be your family’s normal. Our hirsutism or just hairy test can help you think this through.

Idiopathic hirsutism: sensitive follicles

Some women have clearly increased hair growth but normal androgen levels, regular ovulation and normal ovaries. This is called idiopathic hirsutism. The leading explanation is that the hair follicles themselves are more sensitive, either because they convert more testosterone into its stronger form, DHT, or because their androgen receptors respond more strongly^[2]. How strongly follicles respond to androgens varies between people^[2]. There is no simple genetic test for this, but in practice it often shows up in several women of the same family.

PMOS runs strongly in families

PMOS is the most common cause of hirsutism. Its new name was agreed in 2026 through a global consensus process^[3], so you will still see “PCOS” in most research.

The best-known twin study comes from the Netherlands. Researchers looked at more than 3,000 twins and sisters of twins and found that if one identical twin had the condition, the other was much more likely to have it too than in non-identical twins or ordinary sisters (a correlation of 0.71 versus 0.38)^[4]. The authors concluded that the familial clustering is largely explained by genetic factors^[4]. A later review of the genetics literature summarizes twin-study heritability at approximately 70%^[5].

Family studies show the same pattern. In one US study, 24% of mothers and 32% of sisters of women with the condition also had it when examined, compared with about 4% in the general population^[6].

But there is no single “PMOS gene.” Genome-wide studies have found up to 19 genetic regions linked to the condition, and together they explain less than about 10% of its heritability^[5]. In other words, many small genetic effects add up, and lifestyle, weight and the environment before birth probably also play a role. The same review notes that male relatives of women with the condition also seem more prone to type 2 diabetes and metabolic syndrome^[5].

NCAH is directly inherited

Non-classic congenital adrenal hyperplasia (NCAH) is less common, but it is the clearest example of a hereditary cause of hirsutism. It is usually caused by changes in the CYP21A2 gene, which affect an enzyme called 21-hydroxylase in the adrenal glands^{[7], [8]}. As a result, the adrenals make more androgens.

NCAH is autosomal recessive^[7]. That means a person needs two altered copies of the gene, one from each parent, to have it^[9]. Parents who each carry one copy usually have no symptoms.

How common it is depends a lot on ancestry. One review estimates it affects about 1 in 1,000 people of European descent, but about 1 in 27 Ashkenazi Jews, 1 in 53 Hispanics, 1 in 62 people of former Yugoslav origin and 1 in 300 Italians^[7]. Another review gives a range of 1 in 200 to 1 in 1,000 for European populations and also highlights Ashkenazi Jews as a higher-risk group^[8]. In women referred for androgen excess, one large study found NCAH in 4.2%^[7].

What NCAH means for siblings and children

• Siblings: If you have NCAH, your brothers and sisters may have it too, even if they have no symptoms. Many people only find out after a family member is diagnosed and others get tested^[7].
• Children: Your child would only have CAH if your partner also passes on an altered gene. Experts recommend genetic counseling and testing your partner before pregnancy^{[7], [8]}.
• The numbers: One review estimates that 1.5-2.5% of babies born to mothers with NCAH have the classic, more serious form of CAH, and about 15% have NCAH^[7]. If the partner carries no relevant gene change, the risk of classic CAH is close to zero^[7].

This is why it matters to know whether your hirsutism is caused by NCAH rather than PMOS. The two can look very similar, and a simple morning blood test (17-hydroxyprogesterone) is usually the first step. See our guide to hirsutism blood tests.

What is usually not inherited

Some causes of hirsutism have little or nothing to do with family history:

• Medications: Testosterone, anabolic steroids and some other drugs can cause hair growth. This stops being a factor once the drug is stopped or adjusted.
• Androgen-secreting tumors: Tumors of the ovary or adrenal gland are rare and are not considered hereditary in the vast majority of cases. Rapid new hair growth, a deepening voice or other signs of virilization need prompt medical attention.
• Cushing’s syndrome: The most common cause is taking steroid medicines like those used for asthma, arthritis or lupus. Tumors can also cause it, and familial forms exist but are rare^[9].

What to tell your doctor about your family

When you see a doctor about hirsutism, family history is useful information. Mention if any relatives have:

• PMOS or PCOS, or symptoms like irregular periods, acne and excess hair
• NCAH or CAH, or a child born with “ambiguous genitalia” or a salt-wasting crisis
• Infertility or trouble getting pregnant
• Type 2 diabetes, prediabetes or gestational diabetes
• Ashkenazi Jewish, Hispanic or southern European ancestry, since NCAH is more common in these groups^[7]

If you are unsure which specialist to see, our article on which doctor is best for hirsutism may help.

What about my daughter?

If you have hirsutism or PMOS, it is natural to worry about your daughter. A higher family risk is not a diagnosis, and many daughters of women with PMOS never develop it.

During puberty, some hair growth, acne and irregular periods are normal. The international PCOS guideline points out that irregular cycles are common in the first years after periods begin and advises against using ovarian ultrasound to diagnose the condition in teenagers^[10]. Doctors are therefore cautious about labeling a teenager too early.

It makes sense to see a doctor if your daughter:

• Has signs of puberty, like pubic or underarm hair or body odor, before age 8
• Develops hair growth that is rapid, severe or comes with a deepening voice
• Has very irregular or absent periods more than a couple of years after her first period
• Is distressed about her hair, whatever its cause

If you notice hair in a baby or toddler, our separate article on hirsutism in babies, toddlers and kids explains what is common and when to ask a pediatrician. Above all, try not to pass on worry. Talking calmly about bodies and hair, and letting her choose whether and how to remove hair, can matter as much as any test.

FAQ

If my mother has PMOS, will I get it?

Not necessarily. Your risk is higher than average, and one study found that about a third of sisters and a quarter of mothers of affected women also had the condition^[6]. But most of the genetic risk comes from many small effects, not a single gene^[5], and weight and lifestyle also matter.

Is there a genetic test for PMOS?

No. Research has found many genetic regions linked to PMOS, but they explain only a small part of the risk^[5]. Diagnosis is still based on symptoms, blood tests and sometimes ultrasound^[10].

Can NCAH skip a generation?

Yes. Because it is recessive, carriers usually have no symptoms, so it can appear in a family without any obvious previous case^{[7], [9]}. That is why testing family members and partners can be useful once one person is diagnosed.

My whole family is hairy. Do I have hirsutism?

Maybe not. Normal hair amount varies widely by ancestry^[2]. If your periods are regular and there are no other signs of high androgens, your hair may simply be normal for your family. It is still worth checking with a doctor if the hair bothers you or changes suddenly. See also how much facial hair is normal for a woman.

Key takeaways

• Family and ethnic background shape how much hair is normal for you and how sensitive your follicles are^[2].
• PMOS has a strong genetic component, with twin studies suggesting around 70% heritability^{[4], [5]}, but no single gene causes it.
• NCAH is directly inherited (autosomal recessive) and more common in some groups, including Ashkenazi Jews^{[7], [8]}.
• Medications, tumors and most cases of Cushing’s syndrome are not inherited^[9].
• Tell your doctor about family history of PMOS, NCAH, infertility and diabetes.
• For daughters: Stay calm, remember that puberty is messy, and see a doctor for very early, rapid or distressing changes^[10].

Sources

1. myHirsutism. Hirsutism Survey 2019: responses from 269 women with hirsutism, collected January-February 2019. Survey results
2. Escobar-Morreale HF, Carmina E, Dewailly D, et al. Epidemiology, diagnosis and management of hirsutism: a consensus statement by the Androgen Excess and Polycystic Ovary Syndrome Society. Hum Reprod Update. 2012;18(2):146-170. PubMed 22064667
3. Teede HJ, Bahri Khomami M, Morman R, et al. Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process. Lancet. 2026;407(10545):2329-2339. PubMed 42119588
4. Vink JM, Sadrzadeh S, Lambalk CB, Boomsma DI. Heritability of polycystic ovary syndrome in a Dutch twin-family study. J Clin Endocrinol Metab. 2006;91(6):2100-2104. PubMed 16219714
5. Hiam D, Moreno-Asso A, Teede HJ, et al. The Genetics of Polycystic Ovary Syndrome: An Overview of Candidate Gene Systematic Reviews and Genome-Wide Association Studies. J Clin Med. 2019;8(10):1606. Full text
6. Kahsar-Miller MD, Nixon C, Boots LR, Go RC, Azziz R. Prevalence of polycystic ovary syndrome (PCOS) in first-degree relatives of patients with PCOS. Fertil Steril. 2001;75(1):53-58. PubMed 11163816
7. Livadas S, Bothou C. Management of the female with non-classical congenital adrenal hyperplasia (NCCAH): a patient-oriented approach. Front Endocrinol. 2019;10:366. Full text
8. Adriaansen BPH, Schröder MAM, Span PN, et al. Challenges in treatment of patients with non-classic congenital adrenal hyperplasia. Front Endocrinol. 2022;13:1064024. Full text
9. Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). What causes adrenal gland disorders? NICHD
10. Teede HJ, Tay CT, Laven JJE, et al. Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J Clin Endocrinol Metab. 2023;108(10):2447-2469. PubMed 37580314