Sex refers to the male and female duality of biology and reproduction. Unlike organisms that only have the ability to reproduce asexually, many species have the ability to produce offspring through meiosis and fertilization. Often, individuals of the two sexes attract one another and communicate their readiness to procreate through biological changes, or, in social species, through courtship behaviours.
An organism's sex is defined by its biological role in reproduction, not according to its sexual or other behavior. The female sex is defined as the one which produces the larger gamete and which typically bears the offspring. In contrast, the male sex has a smaller gamete and rarely bears offspring. In some animals and many plants, sex may be assigned to specific structures rather than the entire organism. Earthworms, for example, are normally hermaphrodites.
Level Characteristics Female Male
Primary
Sex chromosomes XX XY
Gametes Ova Spermatozoa
Sex organs Ovaries Testes
Predominant Sex hormones Estrogen and Progesterone Testosterone
Hormonal Regime Cyclic during fertility Tonic (largely unchanging)
Anatomy of internal genitalia clitoral crura, vagina, uterus, fallopian tubes corpora cavernosa, urethra, prostate, seminal vesicles
Anatomy of external genitalia glans clitoris, labia, vulva, clitoral hood, perineal urethra penis, scrotum, foreskin, fused perineum
Secondary
Skeletal Structure Relatively shorter,
wider in hips Relatively taller,
wider in shoulders,
bigger chest
Face Rounded jaw Bigger nose bone, brow bone, squarer jaw,
facial hair
Body fat and muscle Relatively more fat Relatively more muscle
Fat Distribution More in buttocks, hips and thighs More in abdomen
Body form development "Hourglass" shape: 8 "Triangular" shape: ▼
Other Breasts Adam's apple and body hair
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