Look at your mother’s father?
The baldness myth

Where the idea comes from

The AR gene, which makes the androgen receptor, is on the X chromosome. Men get their only X from their mothers, hence “baldness comes from your mother’s side.” MedlinePlus confirms that AR variants are associated with male pattern hair loss.

What a large study found

MedlinePlus describes the inheritance pattern of male pattern hair loss as unclear because many genetic and environmental factors are involved, and notes that having a close relative with patterned hair loss is a risk factor. That means looking at both sides of the family, not just your mother’s.

The sex-influenced model

Textbooks use baldness as an example of sex-influenced inheritance: with the same genotype, one copy is enough in men, while women need two. It helps explain the difference between men and women, but as the study shows, many more genes are involved.

Try it in the app

The Android app Genetic Kids Lab calculates Balding tendency with this sex-influenced model, so you can see how sons and daughters differ.

1

Set Balding tendency

Near the bottom of Parent traits, set Balding tendency to Yes or No for each parent.

2

Compare several virtual children

Tap Draw one child several times and compare the Balding tendency line on boys’ and girls’ cards. Different results by sex from the same parents is the hallmark of the sex-influenced model.

FAQ

Related guides

• Left-handedness genetics — how parents’ handedness relates to a child’sAbout 10% left-handed · about 25% heritable · dozens of genes plus prenatal factors
• Dimples, earlobes, tongue rolling and double eyelids — dominant or myth?Textbook example ≠ proven single gene · weak evidence for dimples · tongue rolling retracted
• Traits that skip a generation — carriers, grandparents and sibling differencesHidden recessive alleles · 3-generation pedigree · same parents, different kids
• All Genetic Kids Lab guides10 guides in one place