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The embryo and subsequent early fetus appear to be sexually indifferent, looking neither like a male or a female. Over the next several weeks, hormones are produced that cause undifferentiated tissue to transform into either male or female reproductive organs. This process is called sexual differentiation.
The human brain. Differences in male and female brain size are relative to body size. [83] Early research into the differences between male and female brains showed that male brains are, on average, larger than female brains. This research was frequently cited to support the assertion that women are less intelligent than men.
Sexual differentiation is the process of development of the sex differences between males and females from an undifferentiated zygote. [1] [2] Sex determination is often distinct from sex differentiation; sex determination is the designation for the development stage towards either male or female, while sex differentiation is the pathway towards the development of the phenotype.
During puberty, a male's erect penis becomes capable of ejaculating semen and impregnating a female. [26] [27] A male's first ejaculation is an important milestone in his development. [28] On average, a male's first ejaculation occurs at age 13. [29] Ejaculation sometimes occurs during sleep; this phenomenon is known as a nocturnal emission. [25]
Male primary sex characteristics are the penis, the scrotum and the ability to ejaculate when matured. Female primary sex characteristics are the vulva, vagina, uterus, fallopian tubes, cervix, and the ability to give birth and menstruate when matured. [1] Hormones that express sexual differentiation in humans include: estrogens such as estradiol
In Olympic weightlifting, male records vary from 5.5× body mass in the lowest weight category to 4.2× in the highest weight category, while female records vary from 4.4× to 3.8×, a weight-adjusted difference of only 10–20%, and an absolute difference of about 30% (i.e., 492 kg vs 348 kg for unlimited weight classes; see Olympic ...
When children become aware of their bodies, the bodies of other children, and the bodies of their parents, they gratify physical curiosity by undressing and exploring each other and their genitals, the center of the phallic stage, in the course of which they learn the physical differences between the male and female sexes and their associated ...
The ideas of differences between the male and female brains have circulated since the time of Ancient Greek philosophers around 850 BC. In 1854, German anatomist Emil Huschke discovered a size difference in the frontal lobe, where male frontal lobes are 1% larger than those of females. [6]