Sex is messy.
It’s not just chromosomes. Or germ cells. Or other binary metrics. Many genetic, environmental, and developmental variations can produce what is considered to be the masculine and feminine traits of the same person. And, scientists say sex should be seen in all its complicated glory.
“Sex is a multifaceted property with several components present at birth and several components developed during adolescence, each of which exhibits variations,” says Kansas, Manhattan. says Sam Sharp, an evolutionary biologist at State University.
However, the definition of biological sex, released by US President Donald Trump, specifies either male or female, based solely on the size of the germ cells they make.
Millions of Americans do not fit into the narrow definition of not making mistakes themselves. And many don’t know that.
in Presidential Order The president, who signed on January 20, argued that there are two unchanging human genders, and that women are defined as “in the concept, those who belong to the gender that produces large germ cells.” According to orders, men make smaller cells.
On February 19th, new Instate Health and Human Service Secretary Robert F. Kennedy Jr. announcement Most federally funded health research agencies should use these definitions to create policies.
In the slight variation from the executive order, HHS defines men as “people of gender who are characterized by a reproductive system with biological functions that produce sperm. People who have a reproductive system that makes eggs A woman as.
“For me, this definition is really painful because it reduces the likelihood that humans will replicate,” says Anna Byerson Rover, a pediatric endocrinologist at Friborg University in Switzerland.
Furthermore, Trump’s definition is not biologically accurate and excludes people who have specific genetic variations and do not produce germ cells or gametes. Orders give them no exceptions. “What does that mean for people who don’t have gametes?” asks Sharp. “That’s an unanswered question for now. But it’s an important question to answer, because you can’t have a definition of sex that doesn’t apply to anyone.”
The definition of sex used to determine who can obtain identification cards and use public toilets should explain variations, they and other researchers say.
Sex is complicated
One of the things Trump’s order is that he has two sizes of germ cells, known as eggs and sperm, or gametes. Egg cells are much larger than sperm. Nathan Lens, a molecular evolutionary biologist at John Jay College of Criminal Justice in New York City, says it’s as close to true binary as nature can get.
But gender is far beyond the size of germ cells, researchers say.
“Biology doesn’t work with binaries often,” says Rent.
Instead, most traits attributed to men and women fall along the spectrum at two peaks. One is the average for women and the other is the average for men. For example, on average, men are taller than women, have more muscle mass, more red blood cells, and have higher metabolism.
But almost no one fits into the peak of all measures for their sex, says Lents. “There are a lot of women who are taller than many men. There are many women who have a higher metabolic rate than some men despite their different averages.
“If you define biological sex purely by gametes, you will ignore most of the things that are actually important to your daily life, including your social life,” he says. “Reducing sex to binary doesn’t really make much sense as to how we actually live.”
Sex does not start with conception
No sex cells are produced at conception. Fertilized eggs are “since they are single cells, they can’t produce gametes,” says Sharp.
In fact, sexual development does not begin until a few weeks after conception. The exact timing is difficult for humans to identify. Because it occurs in the uterus. Many times, before they know that people are pregnant, says Viason Lauber. Approximately six weeks after pregnancy, cells appear that will eventually produce gonads. It creates an ovary and creates an egg or testicle to produce sperm. But for weeks, these cells “doublely cannot distinguish” from each other, she says.
Scientists believed that embryos developed automatically as females, unless specific instructions were given to become males. However, over the past decade, researchers have discovered that for embryos to develop as women, they need to actively dismantle the structures of male production and build structures that support female reproduction.
During a pregnancy of about 8 weeks, certain cells that become testes begin to produce testosterone, a hormone that is important for the development of the scrotum, penis, and other male genitals. However, at this point the man still does not produce sperm. This is because testosterone production decreases around the 20th week of pregnancy, and puberty is re-entangled, and immature cells do not return again until they become deformed into sperm.
The ovaries do not produce sex hormones in the fetus. The uterus, fallopian tubes and vagina also develop without hormone input, says Biason-Lauber. These cells are packed with animations suspended until adolescence so that they can mature and be released, but women are born with all the eggs they have ever made.
Sex chromosomes are different
These developmental processes are often directed in part by what is called gender chromosomes. This name is somewhat misnomer, as these two chromosomes (called X and Y) have a wide range of responsibility beyond gender.
The X chromosome contains hundreds of genes, including many genes involved in the whole body’s process, such as blood clotting, chromophoresis, and brain development. Much smaller Y chromosomes contain genes important for male sexual development and fertility, but they also play a role Immunity, heart health cancer.
Women generally have two X chromosomes, while men usually have X and Y chromosomes. But there are many variations in the theme, says Biason-Lauber. For example, in Turner syndromewomen lack one X chromosome. “They don’t have gametes,” she says. Instead, these women have what is called the gonads of streaks. “They have collagen instead of the ovaries.” They have a uterus.
This leads to Biason-Lauber as saying, “If the definition of a woman is the presence of large cells, what are these? [people]? ” Turner syndrome is not that rare, she says, which occurs in one of the 2,000-2,500 babies of women born. Some people may not be diagnosed or may not be diagnosed until adulthood.
Approximately one in every 650 male babies born has more than two X chromosomes and one Y. Kleinfelter syndromedo not produce sperm. Biason-Lauber said many people don’t realize they carry extra chromosomes until they get fertility treatment. These people have testes and penis, but do not produce small germ cells and therefore do not conform to the government’s definition of males.
The Y chromosome contains genes called sry It is important, but not essential for male sexual development. Sometimes, when chromosomes divide before sperm production, sry It pops out of the Y chromosome and attaches to X or another chromosome. When hitchhiking sry The gene can occur in people suffering from two X chromosomes rather than the rest of the y chromosome. Plus, wandering sry gene. These people often develop as males.
Some people have X and Y chromosomes, but they have versions of sry or other genes It does not spur the development of a typical male. Those people develop as women, but don’t make gametes.
Others with X and Y may have genetic mutations that prevent the body from responding to testosterone, called androgens, and other male sex hormones. People with Androgen’s insensitivity There is a testis in the abdomen, but the rest of the body develops as a female. “These people will have small cells, but they are not male,” says Biason-Lauber.
Many other gene variations may also prevent the production of large or small germ cells. Some people have Various combinations of sex chromosomes With different cells in the body.
It’s not so rare to be intersex
Approximately 1.7% of the population is intersex It doesn’t fit in a box for men and womenaccording to Interaction, an advocacy organization for intersex youth. It is as common as having naturally red hair. Intersex people may have a variety of sexual developmental differences, including Turner syndrome, androgen insensitive, and Klinefelter syndrome.
Some may be born together Both ovarian and testicular tissuestherefore, they could be classified as both male and female under the terms of the executive order, says Sylvan Fraser Anthony, Law and Policy Director for Interaction.
Intersex individuals often undergo surgery as infants and infants, and undergo surgery to match the gender chosen by their parents. They may also need to take hormones like estrogen and testosterone to maintain their health, Sharp says. Sharp worries that using the binary definition of sex, intersex people can deny access to health care.
These sexual hormones “play an important role in many developmental aspects, such as whether the skin is painful, how high it is during adolescence, and whether bone density can be maintained,” they say. says.
Choosing a single definer of sex will make the confusion sow.
“if [they] There are a lot of people who use chromosomes and get very surprised to find out they are male,” says Lents. “If they use gametes, they’ll rule out some individuals… but they could also open the door to include people they don’t intend to. “For example, those who have X and Y chromosomes but make female gametes are eligible under the definition of competing in female sports.
“The biology of sex and gender makes that very clear,” Lents says. “These are not difficult categories with clear definitions.”
