Did I Get My Hair Loss From Mom or Dad?

The Truth Behind the “Baldness Comes From Your Mother's Side” Myth

If you're a man beginning to notice that your hairline isn't occupying quite as much real estate  as it once did, family gatherings can suddenly become genealogical research.

Dad still has plenty of hair.

Grandpa on Mom's side was bald.

Uncle Frank started thinning at 28.

And somebody inevitably announces:

“Baldness comes from your mother's side.”

Case closed.

Except it isn't.

The genetics of common pattern hair loss are considerably more complicated—and considerably more interesting.

Why everybody blames Mom

There actually is some science behind the old story.

Men ordinarily inherit their X chromosome from their mother and their Y chromosome from their father.

And sitting on the X chromosome is a particularly important region associated with male-pattern hair loss: the AR/EDA2R locus, which includes the androgen-receptor gene.

The androgen receptor matters because androgenetic alopecia involves genetically susceptible scalp follicles responding to androgens—particularly the effects associated with dihydrotestosterone, or DHT. Over time, susceptible follicles progressively miniaturize and produce finer, shorter hairs.

Researchers discovered a strong association between the X-chromosomal AR region and male-pattern baldness. Because a son receives that X chromosome from his mother, the finding provided genuine biological support for something families had seemingly noticed for generations:

Mom's side matters.

And that's probably where the famous advice about inspecting your maternal grandfather gets its staying power.

But then genetic science got much better.

Dad would like a word

Genome-wide studies have now identified many genetic regions associated with male-pattern baldness.

And here's the important part:

Most of them aren't on the X chromosome.

They're on the autosomes—the ordinary chromosomes that a child inherits from both mother and father. A major genetic analysis identified 63 male-pattern-baldness risk loci; only six were X-linked, while the remaining 57 were autosomal.

A more recent comprehensive review reaches the same broad conclusion: the great majority of identified susceptibility loci are autosomal and therefore can be inherited through either parental line. The X chromosome contains some particularly influential risk regions, but it is only part of the genetic picture.

So:

Can Mom contribute to your baldness? Absolutely.

Can Dad contribute? Absolutely.

Can both sides pile their genetic chips onto the table simultaneously?

Unfortunately, yes. 😂

But what about my maternal grandfather?

Here's where family genetics gets especially fun.

Suppose you're male.

Your mother gave you an X chromosome. That X came originally from one of her two X chromosomes—one inherited from her mother and one from her father.

Therefore, your maternal grandfather really can be an important clue.

But he isn't a crystal ball.

Your mother's genetic contribution contains DNA inherited from both of her parents, and you also inherited half of your autosomal DNA from your father.

So looking across the Thanksgiving table at Grandpa's gleaming pate and concluding:

“Well, there goes my hair.”

is getting considerably ahead of the evidence.

Your father, paternal grandfather, maternal grandmother, paternal grandmother and wider family history can all contain relevant information.

In fact, scientists have specifically noted that the frequently observed resemblance between bald fathers and bald sons cannot be explained by an X-linked androgen-receptor gene, because fathers don't normally give their X chromosome to their sons. Autosomal inheritance provides an obvious route for that father-son resemblance.

There isn't a single “baldness gene”

This may be the biggest misconception of all.

You don't generally inherit one switch labeled:

HAIR: ON / OFF

Androgenetic alopecia is polygenic.

That means many genetic variants contribute to susceptibility. Large genomic studies have identified numerous associated regions involving androgen signaling, follicle development and other biological pathways.

Think of it less like inheriting blood type and more like inheriting height.

Mom contributes something.

Dad contributes something.

Grandparents contributed to them.

Different combinations of variants accumulate.

Then age, sex and hormonal biology influence how that genetic predisposition actually manifests.

That's why two brothers can have surprisingly different heads of hair.

They have the same parents—but they did not inherit identical combinations of their parents' DNA.

One brother can begin thinning substantially at 30 while another retains considerably more hair at 60.

Genetics deals the cards.

It doesn't necessarily deal every sibling the same hand.

What about women?

This is another reason the “mother's father” rule breaks down.

Women experience androgenetic hair loss too, but female-pattern hair loss isn't simply male-pattern baldness occurring in a woman. Its genetic architecture remains less completely characterized, and current research suggests there may be meaningful biological and genetic differences between male and female patterned hair loss.

Women can inherit susceptibility from both sides of the family as well.

And because women normally have two X chromosomes—one from each parent—the simple maternal-X explanation used for sons doesn't apply in the same way.

So whose fault is it?

This is perhaps the scientifically correct answer:

Nobody's.

Your mother didn't give you baldness.

Your father didn't give you baldness.

They each gave you approximately half of a remarkably complicated genetic instruction manual assembled from generations of ancestors.

Some of the variants influencing male-pattern hair loss can arrive through Mom.

Others can arrive through Dad.

And one particularly important region happens to sit on the X chromosome that a son receives from his mother—which is how a complicated genetic story became simplified into the enduring folk rule:

“Baldness comes from your mother's side.”

The folk wisdom wasn't invented from nothing.

It simply stopped about halfway through the genetics.

Want to predict your future hair?

Don't inspect just one grandfather.

Look at everybody.

Look at your father and both grandfathers. Look at your uncles. Look at your mother's brothers. Look at your father's brothers. And don't overlook thinning among the women in the family simply because it may present differently.

A strong pattern of early hair loss throughout a family is much more informative than whether one particular grandfather was bald.

Even then, family resemblance gives you probabilities—not destiny.

And perhaps that's the best way to remember the genetics of baldness:

You can inherit hair-loss susceptibility from Mom.

You can inherit it from Dad.

And if baldness runs enthusiastically through both sides of the family, your follicles may have received a remarkably bipartisan mandate.

😂

Sources & Further Reading

Heilmann-Heimbach S. et al. Male-pattern hair loss: Comprehensive identification of the associated genes as a basis for understanding pathophysiology.

Heilmann-Heimbach S. et al. Meta-analysis identifies novel risk loci and yields systematic insights into the biology of male-pattern baldness. Nature Communications.

Hillmer A.M. et al. Genetic Variation in the Human Androgen Receptor Gene Is the Major Determinant of Common Early-Onset Androgenetic Alopecia. American Journal of Human Genetics.

Lolli F. et al. Androgenetic alopecia: a review.