Biological sex

Biological Sex

Biological sex refers to the physical characteristics that define humans and other organisms as male or female. These characteristics include chromosomes, gonads, hormone levels, internal and external genitalia, and secondary sexual characteristics. Biological sex is typically categorized as male or female, though some individuals may be intersex, possessing characteristics of both sexes.

Chromosomes

Humans typically have 46 chromosomes, arranged in 23 pairs. The 23rd pair, known as the sex chromosomes, determines an individual's biological sex. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY). Variations in these chromosomes can result in different intersex conditions.

Gonads

Gonads are the organs that produce gametes (sperm or eggs) and sex hormones. In males, the gonads are the testes, which produce sperm and testosterone. In females, the gonads are the ovaries, which produce eggs, estrogen, and progesterone.

Hormones

Sex hormones play a crucial role in the development and regulation of secondary sexual characteristics and reproductive functions. The primary male sex hormone is testosterone, while the primary female sex hormones are estrogen and progesterone.

Genitalia

External genitalia are the visible sex organs. In males, this includes the penis and scrotum. In females, this includes the vulva, which encompasses the labia, clitoris, and vaginal opening. Internal genitalia include structures such as the uterus and fallopian tubes in females, and the vas deferens and prostate gland in males.

Secondary Sexual Characteristics

Secondary sexual characteristics are features that appear during puberty and distinguish the two sexes but are not directly involved in reproduction. In males, these include facial hair, a deeper voice, and increased muscle mass. In females, these include breast development, wider hips, and a higher percentage of body fat.

Intersex

Intersex individuals are born with physical sex characteristics that do not fit typical binary notions of male or female bodies. This can include variations in chromosomes, gonads, hormones, or genitalia. Intersex is a naturally occurring variation in humans and is distinct from gender identity and sexual orientation.

Related Pages

• Sexual differentiation
• Gender
• Sexual reproduction
• Human reproduction
• Sexual dimorphism
• Intersex