Male vs. Female

Science usually uses the word "sex" to differentiate between male and female. This isn't as simple as it sounds. There are many different things that can determine a person's sex. Interestingly enough, these things don't always point to the same category. For instance, some people might view themselves as belonging to one sex while society views them as belonging to the other. Certain sexual anomalies can cause a person with a chromosomal sex of male to appear female because of abnormal morphologies like breast development. The following are different ways for determining sex.

Germ Cell Sex

is determined by the type of gametes produced. A gamete is a cell made for fertilization, which contains only half of the individual's genetic material.

  • If eggs (ova) are produced, you're female.
  • If sperm (spermatozoa) are produced, you're male.

Chromosomal Sex

is determined by the sexual chromosomal type. Both parents contribute 23 chromosomes to our genetic makeup. One of the 23 chromosomes carried by the sperm is the sex-determining chromosome. Therefore it's the father's contribution that determines the sex of the child. Every father has a chromosomal pair consisting of one X chromosome and one Y chromosome, while every mother has a chromosomal pair consisting of two X chromosomes. The Y chromosome triggers the development of testes. The testes then produce hormones that cause the offspring to develop as a male. Without testes a human naturally develops as a female. So...

  • If the sperm is carrying the X sex chromosome, you'll end up with an XX combination and you'll be female.
  • If the sperm is carrying the Y sex chromosome, you'll end up with an XY combination and you'll be male.

Endocrinologic Sex

is determined by gender specific hormonal patterns. Hormones are chemicals that are produced by glands, travel through your blood, and effect other parts of your body. They can stimulate other organs or cause you to behave a certain way. Depending on your hormonal makeup at a certain time it might cause a woman to menstruate or cause a male to be sexually aroused, for example. The sex hormones are those hormones that are produced in the testes, ovaries or placenta that effect a person sexually. They can be classified into 3 groups: androgens, (masculinizing hormones such as testosterone), estrogens (feminizing hormones) and progestins (hormones related to pregnancy).

  • If you have high levels of testosterone, you're male.
  • If you have high levels of estrogen, you're female.

All Hail Testosterone!

Testosterone is a predominantly male hormone, although it is found in both men and women. During development, high levels of testosterone cause the penis and testes to form. It causes hair to grow on the face and chest. People often use the word testosterone when cracking "male chauvinist pig" jokes. It gets blamed for men's love for football, the remote control, flexing in front of the mirror and women's breasts. The truth is that testosterone is a hormone that has been selected over evolution to push us competitively and sexually. Since the beginning of the ice age, testosterone encouraged men to compete with each other for the right to mate with a woman. This made it more likely that the physically and mentally stronger males were able to reproduce, thus strengthening the species as a whole. The sex drive provided by testosterone ensured that we would reproduce in order to sustain and increase the population. Neanderthals failed to sustain their population, and as a result are extinct today. Humans have become one of the most successful species on the planet, because we were able to sustain a strengthened population largely due to testosterone. Today, the effects of testosterone remain. However they often have to be suppressed in order to live peacefully in dense populations. Men are still competitive when seeking a mate. Men still have a very strong sex drive, causing them to think about sex frequently throughout each and every day. If it weren't for testosterone, men would be a bunch of wimps with no testicles and absolutely no desire to have sex or children. High levels of success in men have been found to be directly associated with high levels of testosterone. Women might also find it amusing that testosterone is a derivative of estrogen. So think of that the next time you make fun of the wonderful hormone called testosterone.

All Hail Estrogen!

Yes, estrogen is associated with fat deposits on the backs of thighs and water retention. However, estrogen is a wonderful hormone that provides so many good things as well. During puberty, estrogen is responsible for the development of the vagina, uterus and the fallopian tubes. Before pregnancy estrogen insures that the uterus is thick and well supplied with blood and nutrients. Estrogen causes the maturation of a fertilized egg, and implantation of the fertilized egg in the uterine wall. In short, none of us would be here if not for this amazing hormone. Mammary development and growth is initiated by estrogen so newborn babies and men can certainly thank this hormone for that. It is estrogen that causes the bones of men and women to grow. This is why girls start their growth spurt earlier than boys. Girls have a high level of estrogen from the beginning of puberty. Boys are too busy converting estrogen into testosterone to develop their male genitalia. By the time they have enough excess estrogen to stimulate bone growth, girls have had a 2-year head start. Dropping levels of estrogen in the body is what causes PMS (premenstrual syndrome), so you can thank estrogen during the rest of the month when you're not depressed, irritable, or experiencing other unpleasant symptoms. Estrogen prevents many of the symptoms characterized menopause as well. Once the estrogen levels drop during a woman's 40s or 50s, she is allowed to experience hot flashes, night sweats, mood swings, forgetfulness, or a reduced coordination. This is why older women take estrogen pills. So thank the wonderful hormone estrogen for making our lives both possible and more enjoyable.

Gonadal Sex

is determined by the tissue found in the gonads.

  • If your gonads contain ovarian tissue (ovaries), you're female.
  • If your gonads contain testicular tissue (testes), you're male.

Morphological Sex

is determined by the morphology (form and structure) of the external sexual organs.

  • If you've got a penis and scrotum, you're male.
  • If you've got a vulva and breasts, you're female.

Phenotypic Sex

is determined by the results of hormonal influences.

  • If you've developed breasts, a vulva, and internal female genitalia, you have a menstrual cycle, and you have a motherly instinct, you're phenotypic sex is female.
  • If you've developed a penis, testicles, chest hair, an aggressive behavior, and a heightened sex drive, you're phenotypic sex is male.

Psychological Sex

is determined by the individual's self-image.

Social Sex

is determined by the society's view of the individual.

Behavioral Sex

is determined by the individual's behavior.

So as you can see, science looks at sex in many different ways.

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