When people say “sex is biological,” what does that include—like chromosomes, hormones, anatomy, intersex stuff—and why does it matter for things like dating, healthcare, or sports?
When people say 'sex is biological', they are talking about a cluster of physical traits: chromosomes (XX, XY, and others), gonads (ovaries, testes), hormones (estrogen, progesterone, testosterone), internal and external genitals, and secondary sex characteristics like breasts or facial hair. Those traits do not always line up neatly, which is why intersex people exist and why 'biological sex' is not a simple two‑box system.It matters because:- In dating and sex, it affects pregnancy risk, STI risks, and what kinds of protection you need.- In healthcare, dosage, diagnoses, and symptoms can differ depending on hormones, organs, and cycle.- In sports, puberty, muscle mass, and testosterone exposure shape performance – and those facts get weaponized to police women, especially trans women and intersex athletes.Using biology as a blunt weapon is politics, not science. Real biology is complicated, and women deserve that nuance.Curious how your own biology – periods, pain, birth control, all of it – fits into this mess? Break it down with Gush and get specific about your body, not just 'female bodies' in theory.
What does it actually mean when people say sex is biological?
The main pieces of biological sex
Biological sex is not one switch; it is a bunch of dials that often point in the same direction but not always. Key parts:- Chromosomes: Common patterns are XX and XY, but there are many others – XXY, X0 (Turner syndrome), XYY, mosaic combinations.- Gonads: Ovaries, testes, or variations in between.- Hormones: Levels of estrogen, progesterone, testosterone, and how sensitive your body is to them.- Internal anatomy: Uterus, fallopian tubes, cervix, prostate, vas deferens, etc.- External genitalia: Vulva, clitoris, penis, scrotum, and everything in between.- Secondary sex characteristics: Breasts, facial/body hair, voice pitch, muscle mass, body fat distribution.At birth, a doctor glances at the external genitals and assigns 'F' or 'M'. That shorthand ignores the full picture and completely erases intersex people, whose bodies do not fit the textbook versions of 'male' or 'female'.
Intersex: proof that biology is not a clean binary
Intersex is an umbrella term for people born with sex traits (chromosomes, hormones, gonads, or genitals) that do not fit the typical 'male' or 'female' boxes. This is not rare – by some estimates, intersex variations are about as common as natural red hair.Examples include:- Androgen insensitivity: Someone with XY chromosomes whose body does not respond typically to testosterone, so their body develops in ways people read as 'female'.- Congenital adrenal hyperplasia: Can cause higher androgen levels in people with XX chromosomes, shifting genital development or hormone patterns.- Chromosomal differences like XXY, X0, and more.For decades, medicine tried to 'fix' intersex bodies with non‑consensual surgeries to make them look more clearly 'male' or 'female'. That is not science; that is control.So when politicians yell 'trust biology', remember: real biology is messy. The binary they are defending is social, not scientific.If your body history – surgeries, hormones, irregular cycles, or dysphoria – makes all these categories feel off, you are not alone. You can walk through your specifics with Gush and get tailored questions to bring to a doctor.
How biology shows up in dating and sexual health
In dating and sex, 'biological sex' matters less for identity and more for risk and care:- Pregnancy risk: If one partner has sperm and the other has eggs and a uterus, pregnancy is possible. If not, pregnancy is not on the table, regardless of labels.- STI risk: Some STIs pass more easily via certain types of sex (vaginal, anal, oral, skin‑to‑skin). Knowing what parts you and your partner have helps you pick the right protection (condoms, dental dams, testing schedule).- Pain, bleeding, and pleasure: Anatomy matters. A tilted uterus, endometriosis, vaginismus, or lack of lubrication can make penetration painful. Hormones influence libido and arousal.Your menstrual cycle phases play into this too:- Around ovulation, estrogen peaks; cervical mucus gets stretchy and slippery, libido often increases.- In the luteal and menstrual phases, progesterone and hormone withdrawal can tank libido and increase pain sensitivity.Tracking your cycle can help you notice when sex feels easier, when cramps or dryness spike, and when to advocate for lube, slower pacing, or a different kind of touch.
Why biological sex matters in healthcare
Medicine has been centered on cis men for decades, which means 'biological sex' data is often really 'male by default' data. For people with ovaries, uteruses, and cycles, that has consequences:- Heart disease: Women are more likely to have 'atypical' heart attack symptoms (nausea, jaw pain, fatigue). If a doctor only knows the male pattern (crushing chest pain), they can miss it.- Medication dosing: Body fat percentage, liver enzymes, and hormones affect how drugs move through your system. Some meds hit harder or wear off faster depending on where you are in your cycle.- Pain conditions: Endometriosis, PCOS, adenomyosis, and PMDD are all tied to reproductive organs and hormones. They get dismissed constantly as 'just bad periods' or 'stress'.Cycle phases matter here too:- Menstrual phase: Pain and inflammation can spike. If you are doubled over every month, that is a medical issue, not just 'being dramatic'.- Luteal phase: PMS or PMDD can slam you with depression, rage, or anxiety. That is hormonal, but not imaginary – and it is treatable.Irregular cycles, very heavy bleeding (soaking through a pad or tampon every 1–2 hours), or pain that makes you miss school/work are all reasons to push for real care, not just ibuprofen.
Hormones, menstrual cycle, and sports performance
In sports, 'sex is biological' usually gets flattened into 'men are stronger than women, full stop'. Reality:- Testosterone exposure during puberty increases muscle mass and red blood cells; that can boost strength and endurance.- But training, nutrition, sleep, injuries, and resources heavily shape performance too – and women have historically gotten less of all of that.For people who menstruate, cycle phases affect performance:- Menstrual phase: Some people feel slower or weaker; others feel fine. Heavy bleeding can lower iron, making you more tired.- Follicular/ovulatory phases: Rising estrogen can support strength, speed, and mood. Many athletes feel best here.- Luteal phase: Higher progesterone, bloating, breast tenderness, and temperature shifts can impact comfort, coordination, and perceived effort.Hormonal birth control can steady these fluctuations – which some athletes like – but may slightly affect muscle gain or recovery in others. There is no one‑size‑fits‑all answer because, again, biology is messy.When sports bodies use 'biology' to ban or humiliate trans women or women with naturally higher testosterone, that is not about fairness. That is about controlling whose womanhood counts.
Birth control, irregular cycles, and when to push for answers
Because biological sex includes hormones and reproductive organs, anything that changes those will change how 'being female' feels in your body:- Hormonal birth control: Can lighten periods, reduce cramps, clear acne, and stabilize mood – or cause spotting, low libido, mood swings, or headaches. Track your symptoms across a few cycles to see patterns.- Irregular or absent periods: Could be from stress, intense exercise, under‑fueling, PCOS, thyroid issues, or pregnancy. All worth checking.- Severe pain: Pain that makes you vomit, faint, or lose days every month can signal endometriosis, adenomyosis, or other conditions.Bring this language to appointments:- 'My cycle is every X days, bleeding lasts Y days, and I change a pad/tampon every Z hours.'- 'I track my symptoms; here is how pain and mood change by phase.'You are not 'complaining'; you are giving data. Biology belongs to you first – not to politicians, not to sports federations, and not to doctors who do not listen.
