Voluntary sterilization is the most popular method of birth control in America. More than 1 million women and men choose to have the procedures every year. Sterilization is surgical birth control—it is intended to be permanent, and it is not easily reversed. Vasectomy is the surgical operation for men. It blocks the vas deferens. Tubal [...]

Paraphilias That Rely on Consent Most paraphilias, like fetishism, are not dangerous and rely on the involvement of consenting partners. Here are some other common paraphilias that rely on consent: Pictophilia. Sexual arousal becomes dependent on viewing pornographic pictures, movies, or videos, with or without a partner. Transvestophilia. Sexual arousal becomes dependent on wearing clothing, [...]

Although the dependence of sexual behavior on gonadal hormones has been demonstrated in numerous experiments involving gonadectomy and hormonal replacement, there are very few research data available on the emergence of sexual behavior during spontaneous pubertal development. The most comprehensive studies on lower mammals have been reported by S?dersten and others who assessed sexual behavior [...]

Infants also can be divided into two categories based on the extent to which they seek close personal contacts—noncuddlers and cuddlers. Noncuddlers reach this developmental stage somewhat later than do cuddlers. Noncuddlers show displeasure at being restricted and contained from the early weeks, initially through restlessness. At nine or ten months, when they can crawl [...]

Rhesus monkeys, if pregnant with a daughter fetus and if injected with testosterone during a critical period, give birth to a baby with female internal reproductive organs (two ovaries, uterus, and fallopian tubes) and male external reproductive organs (a well-developed empty scrotum and a clitorine penis). These masculinized female (hermaphroditic) monkeys have been extensively studied [...]

The problem may lie in one of these areas: • The woman—70 to 75 per cent of infertile couples have a female factor. • The man—30 to 35 per cent have a male factor. • The couple—40 per cent of infertile couples have more than one factor. In some couples no cause will be identified. [...]

A pregnancy usually lasts forty weeks, or close to nine months. This time has been divided up into three ‘trimesters’. Each trimester lasts about three months (or thirteen weeks). During the first trimester (zero to thirteen weeks) conception, implantation in the uterus, and formation of a placenta and embryo occur. In the second trimester, more [...]

The general run-of-the-mill safe-sex, be careful, and don’t share needles rules apply. The fact that people know what they should and shouldn’t do unfortunately does not always stop them from getting the disease. A vaccine has been developed which gives people protection against hepatitis B. It is being given to people at particular risk, such [...]

If there is a drop in the level of hormones floating around the body the egg preventing mechanism can fail, and ovulation may take place. Things which can drop the level of hormone include: Not taking the tablet—If you miss a tablet, or are late (by more than twelve hours), you can’t maintain a high [...]

The stimulating hormones, FSH and I.H, are produced in the brain (init complex interplay between the hypothalamus and the pituitary gland, two parts of the brain). FSH sends a message to the ovary. One of the ovaries (they usually take it in turn) responds by developing follicles, which make potential eggs. There are several follicles [...]