Male pattern baldness is not solely inherited from the maternal side; its causes are still under investigation, but scientists think the genetic component of this type of hair loss involves multiple genes.

A man’s genes can predict his hairline

There’s actually some truth to the idea that you should look at your mother’s father. But genetic research tells us that the full picture is somewhat more complicated. An interesting read on how to use genetics to figure out if you'll go bald (with illustrations).

Male pattern baldness accounts for more than 95% of hair loss in men and is characterized by thinning hair, hair loss, and a receding hairline.

40% of women will have noticeable hair loss by age 50.

In 1909, a top public health official in America wrote in an academic journal that baldness was caused almost exclusively by snug-fitting hats.

We're typically born with all the hair follicles we'll ever have, just as women are born with all their eggs.

Humans may have as many as 100,000 to 150,000 individual hairs on our scalps, growing at a rate of roughly 1 centimeter per month.

Why are women more likely to suffer autoimmune diseases than men?

A majority of Americans with autoimmune diseases have more than one X chromosome, a typical marker of the female biological sex, according to a study published in February of 2024. During fetal development, cells side with one X chromosome over the other, preventing the overproduction of X-chromosome-specific proteins and shutting down the twin chromosome. This article explores how this X-chromosome inactivation can lead to autoimmune disorders by generating antibodies to the body's own tissues.

Telogen effluvium is a common, temporary type of hair loss that can be triggered by severe stress, illness, or other body changes like childbirth—it pushes as much as 70% of hair into its resting phase, causing hair to fall out.

Real-time tracking of individual hair cells has revealed that hairs don't actually get pushed out from the root—instead, hair cells are tugged upward by surrounding tissues that act like tiny motors.

Hair loss after childbirth happens because pregnancy hormones paused the normal hair shedding process during pregnancy, so the hair loss is actually your hair cycle 'catching up' with its normal process several months postpartum.

Almost 80% of people diagnosed with autoimmune diseases are women

Yet it's still unanswered what may account for that difference. To better understand this disparity researchers are exploring factors including hormonal changes that occur around puberty, pregnancy, and menopause, as well as gut microbe differences, and aspects of X-chromosome protein-coding genes. (Some users may encounter a paywall.)

Late-stage clinical trials indicate that a common arthritis drug may be a promising treatment for a leading cause of hair loss.

Stress contributes to gray hair because when the body experiences stress, the sympathetic nervous system releases specific hormones that influence pigment-producing cells.

Some data links schizophrenia to older paternal age and birth complications

Yet both associations are not yet considered firm enough to definitively be causative. Schizophrenia is a multi-causal syndrome and a mixture of factors, including genetics, are widely believed to be behind its development.

Many cancers arise from genetic mutations inherited from your parents

These mutations may happen in response to environmental or lifestyle factors, or may be passed down through family members. Genetic testing can be important in catching certain family cancers early and ensuring patients receive the right treatment for their disease.

How do genetics work?

Perhaps you have your mother’s hair or your grandfather’s eyes. How did you get these traits and not others? Learn how genetics work in this online video game.

80% of schizophrenia cases may be inherited

Some research suggests that anywhere between 60% and 80% of people with schizophrenia had genes that predisposed them to the syndrome. That high rate has fueled interest in further exploration of what environmental and lifestyle factors cause some people with that genetic risk to develop the disease when others with the same genetic risks do not.

It's been about 30 years since a new hair loss drug was approved in the US, and women currently have no approved pills for hair loss.

The gaps in menopause research and their effects

Nearly all studies (99%) researching the biology of aging don’t consider menopause in their setup. A Harvard professor noted that about 75% of aging-related diseases are likely influenced by menopause. In this article, she discusses how gaps in research are negatively impacting how the medical system can effectively treat aging women. Read her analysis of the issue here.

Common genetic disorders

As research continues, it's clear that disease and genetics go hand in hand. Here's a selection of 50 National Human Genome Research Institute (NHGRI) articles providing basic information on genetic, orphan, and rare diseases caused by mutations in DNA sequences, whether inherited from parents or brought about by outside factors.

Rodent research suggests goose bumps may play a role in hair growth—raising questions about if this knowledge could be used to reactive sympathetic nerves in hair follicles to boost hair growth in people.

Cleopatra purportedly recommended grinding up fly heads and rubbing them on areas experiencing hair loss as a treatment.

Early menopause, occurring before age 45, can be triggered by certain risk factors

Some potential causes of early menopause include autoimmune disorders, chemotherapy, smoking, and certain surgeries that cause the body to produce lower levels of estrogen and progesterone.

Scientists identify hundreds of genes responsible for OCD

Researchers analyzed the DNA of more than 53,000 people with OCD and identified 30 areas in the genome linked to the disease, containing 249 genes of interest. Of those, several were linked to other brain disorders, paving the way for genetic treatments of various mental illnesses.

Genetics play a role in the reliability of the body's biological clocks

Growing evidence suggests genetics influence when, how long, and how well one sleeps, meaning insomnia may have a genetic component. While exact insomnia biomarkers have yet to be determined, some genes, including those related to psychiatric disorders, have been implicated.

Scientists have not yet answered what the evolutionary benefit may be of menopause

Few animals are known to experience menopause, raising questions about why it would be evolutionarily advantageous to have women survive past their reproductive years. One leading hypothesis is the grandmother hypothesis—older women and other species known to experience menopause, like whales, can aid families and pass down knowledge to future generations.

Modern genetic testing stems from a 1950s discovery about the cause of Down syndrome.

Less than 1% of aging studies consider menopause and its effects

Nearly all studies researching the biology of aging don't consider menopause in their setup. In part, that's because menopause is difficult to emulate in animal models. Menopause is uncommon in the animal world beyond humans and whales. This presents a problem for medicine and science because about 75% of aging-related diseases are likely influenced by menopause.

Half of human DNA is inherited from each parent

Within most cells reside 23 pairs of chromosomes made of tightly wound DNA, and half of each pair is inherited from each parent. The 23rd pair consists of two X-shaped chromosomes, or one such chromosome paired with a Y chromosome, and determines biological sex.

Here’s how different genetic disorders get passed on

The human genome is complex, as identified by the Human Genome Project. This article digs in to genetic disorders, the most common ones, and how they are diagnosed.

Women experience heightened bone loss after menopause

Both women and men begin to lose some bone density after age 35, on average. But, for the first decade after menopause, women lose bone more rapidly due to the significantly decreased levels of estrogen, putting women at heightened risk of osteoporosis and related bone fractures.

Here's why genetically identical sisters can have different colored eyes

The sequence of DNA that we inherit from our parents encodes directions for making our cells and giving us specific traits. Identical twins have the same DNA sequence, so how can one twin end up with a genetic disorder while the other twin does not? Robin Ball explains how the secret lies in X chromosome inactivation.

Twin studies suggest celiac disease is among the more genetically-linked disorders

Genetics appear to play a larger part in this condition's development than many other autoimmune disorders. Research shows a roughly 60-75% genetic probability that if one identical twin has it, the other will too. Celiac triggers a small intestine attack when people eat gluten, a protein commonly found in wheat, barley, and rye.

How menopause affects mental health

Menopause, a natural biological process, occurs in three stages: perimenopause (hormone fluctuations), menopause (end of menstrual cycles), and postmenopause (12 months without menstruation). Hormonal shifts during this time can affect neurotransmitters, increasing the risk of mood disorders.

The history of the gene: an interactive timeline

Humans didn’t need modern technology to figure out that kids tend to look like their parents. But what did humans believe about genetics before we knew about DNA or cells in general? Explore this interactive timeline to see how philosophers and scientists throughout the ages tried to explain how traits are passed from generation to generation.

Autism occurs among women, too

Males have higher rates of diagnosed autism than females, but recently scientists and people with autism have been exploring if females have been disproportionately missed in screening and if girls are perhaps masking their symptoms better, leading to missed diagnoses.

Less than 1% of people globally have schizophrenia, a syndrome strongly linked to genetics

Schizophrenia's causes remain largely unknown, though scientists suggest it's caused by multiple factors. Its symptoms include disruption of thought processes rather than the exhibiting of multiple personalities. This brief video provides an overview of the condition.

Doctors use three key physical markers to determine biological aging

The length of the ends of chromosomes (known as "telomeres"), the gradual change in collections of DNA molecules called "methyl groups", and the secretion of inflammatory proteins are all used as indicators of biological age.

Multiple genes are associated with Alzheimer's risk, but one particularly well-known disease-associated gene is apolipoprotein E (APOE), which typically encodes a protein that helps carry cholesterol and other fats in the bloodstream.

The anatomy of our hair follicles explains goose bumps

The arrector pili muscle contracts when we're cold or scared, causing hairs to stand up and the skin to form the bumps known as goose bumps. This reaction is typically involuntary.

Late-onset menopause lowers osteoporosis risks, but heightens the risks for certain cancers

Defined as when a woman starts to experience perimenopause after age 55, late-onset menopause is linked to an elevated risk of developing breast, ovarian, and uterine cancers.

Some men may be at elevated risk of inheriting tinnitus

A 2017 Swedish Twin Registry study suggests that bilateral tinnitus—when tinnitus occurs in both ears instead of just one—appears to be heritable, at least in men.

Humanity's reduced body hair slows down wound healing

Cuts to human skin take twice as long to heal compared to chimps and other mammals. Scientists argue this is due to the reduced number of hair follicles on human bodies. Hair follicles contain stem cells which help repair skin cells faster, so as humanity shed its hair over time, so to speak, it also slowed its wound healing.

Around 5 million of our 3 billion DNA letters differ between individuals

Genetic testing examines gene variants to help explain disease symptoms. It explores how genetic differences between individuals can be used to understand risks of developing diseases like Huntington's Disease or passing variants linked to disease onto offspring.

Twin studies helped scientists understand why mosquitoes like some of us more than others

A combination of carbon dioxide output, skin chemistry, genetic factors, hormones, and clothing choice can make us particularly vulnerable to mosquito bites. Watch how mosquitoes responded to one man in the video versus his wife, a research approach typically conducted with identical and fraternal twins to test mosquito attractiveness.

Even if you have some ASD-linked gene variations you may not develop ASD

Individual environment and life experiences affect how genes perform in the body, potentially adding methyl groups to DNA that affect their function and turning genes on and off—which may heighten or reduce disease risk.

Genetics may account for nearly 67% of mosquito attractiveness.

Carrier screening enables individuals without symptoms to see if they carry a gene for disease

Some conditions are autosomal recessive—meaning a person may carry a gene for that condition, but not have symptoms. Cystic fibrosis, sickle cell disease, and Tay-Sachs disease are examples of autosomal recessive diseases in which a person must inherit two copies of a nonfunctioning gene—one from each parent—to develop disease.

Medical experts warn that completing genetic testing for Alzheimer's can be fraught, in part because there's a shortage of genetic counselors to help navigate the findings and their potential implications.

Genes are the basic units of heredity

These segments of DNA—long molecules made of nucleotides that coil into chromosomes—code instructions for making specific proteins, which correspond to different traits. Approximately 98 to 99% of human DNA is non-coding, with functions beyond protein synthesis.