Sexual development generally occurs in a recognized progression in both sexes. The age at the commencement and speed of sexual development often varies. It is often thought to be influenced by both genetic and environmental aspects. It is believed that sexual development starts earlier today than it did several years ago. This is probably due to the progression in nutrition, general health, and living conditions for everyone. In boys, sexual changes begin with enlargement of the scrotum and testes. This is followed by a lengthening of the penis and growth of the seminal vesicles and prostate. The next stage consists of the arrival of pubic hair. Axillary and facial hairs often appear about two years after pubic hair does. A growth surge usually happens a year or so after the testes begin enlarging. The normal age for the first ejaculation is somewhere between 12 and 14. This is often influenced by psychologic, cultural, and biologic factors
In most girls, breast budding is the first perceptible sign of sexual development. This is normally followed closely by the beginning of a growth spurt. It is after this that axillary hair begins to appears. Menarche generally takes place about two years after the beginning of breast development. Most girls start their periods at 12 or 13 years of age. The first sign of sexual motions are often noticed very early. Even before the bodily organs are completely developed, the body has a definite erogenous nature and may experience sexual excitement before its ready. Experts feel that the genital zone plays the most noteworthy role in the process of sexual development.
Most children begin having feelings of sexual attraction sometime during early adolescence. The aim of their attraction is usually a member of the opposite sex, but some people find that they are attracted to people of the same sex. A person’s sexual orientation is their inclination to be attracted to people of the same sex, the opposite sex or of both sexes.
Describe the physiological basis of sexual development and orientation
Sexual orientation refers to a continuing pattern of emotional, romantic, and/or sexual appeal to men, women, or both sexes. Sexual orientation also refers to a person’s intellect of identity based on those attractions, linked behaviors, and association in a community of others who share those appeals. Research has established that sexual orientation ranges along a collection, from exclusive attraction to the other sex to exclusive attraction to the same sex. Yet, sexual orientation is usually talked about in terms of three categories: heterosexual, gay and lesbian and bisexual. This series of behaviors and attractions has been portrayed in various cultures and nations around the world. Many cultures use identity labels in order to describe people who articulate these attractions. In the United States the most general labels are lesbians, gay men and bisexual people.
Sexual orientation is separate from other components of sex and gender, including biological sex which is the anatomical, physiological, and genetic characteristics that are associated with being male or female, gender identity which is the emotional intelligence of being male or female and social gender roles, which are the cultural norms that define feminine and masculine behavior. Sexual orientation is normally discussed as if it were solely a feature of an individual, like biological sex, gender identity, or age. This viewpoint is incomplete because sexual orientation is separate in terms of relationships with others. People articulate their sexual orientation through behaviors with others, including such straightforward actions as holding hands or kissing. Therefore, sexual orientation is strongly tied to the close personal associations that meet intensely felt needs for love, attachment, and intimacy.
Examine the interaction between hormones, the body, and behavior; including sex differences in brain morphology and the hormonal control over sexuality
Hormones that are secreted by the gonads are identified to put forth powerful effects on behavior. In humans it has been shown that the early occurrence of androgens often organizes the male brain to improve certain spatial functions. The hormonal balance can be reinstated to normal by the administration of cortisone. It has been shown that the effects of early androgen exposure can often be seen later in life in the form of behavioral disparities. The requirement for contrast with family members in order to control for widespread intelligence, when dealing with small unique populations, often accounts for the lack of such improvement.
Sexual orientation is a supplementary biological variable that is often predictable to relate to cognitive models. Even though the determining factors of sexual orientation are yet to be completely understood, neuroanatomical studies in humans have shown an early association of these factors to disparities in sexual orientation in some males. A few studies relating to cognitive dissimilarities between homosexual and heterosexual men have found variable properties. These studies have shown that homosexual men achieved lower scores on mental rotation tasks and on tasks involving sampling awareness of the horizontal. There has been some evidence offered that the interaction between hormones, especially the sexual ones may have some fortitude on a personâ€™s sexual orientation. There have been definite sex differences found in brain morphology which is thought to play a role in a personâ€™s sexual orientation as well.
Discuss the affect of the environment on sexual development and orientation
The biological groundwork of sexual orientation, whether it be heterosexuality, homosexuality, or bisexuality has for a long time been a very controversial topic. An increasing body of research has shown that genetics and the environment often work together in order to establish a personâ€™s sexual orientation. Yet, there are many issues that still continue to be blurred. These concerns consist of the amount of sexual orientation that is genetic and how much is shaped by environmental pressures that include family, society, and culture. Another issue has to do with whether sexual orientation is a set trait, or whether it is a matter of environmental influence and might be variable over time. There are two main types of genetic studies that are often carried out. These include classical family, twin and adoption studies and biological studies. These have been found to sustain multiple genetic and environmental factors that determine male and female sexual orientation.
Twin studies are the standard way used to examine the role of genes. Twins that are brought up together often share the same environment. Monozygotic twins share all their genes, while dizygotic twins only share half. Early twin studies found that if one monozygotic twin was homosexual, then there was an increased chance the other twin would also be homosexual. The probability of this was found to be greater for dizygotic twins. It has been found thought, that these studies were potentially prejudiced. They used homosexuals and had relatively small sample size. More recent twin studies have examined all twins in a community with no consideration to sexual orientation. This has provided a large, less biased sample size. Some family studies have found that more homosexuals had homosexual maternal relations as opposed to paternal links. This is thought to sustain a genetic factor on the X chromosome and environmental pressures although there have been other studies that have not found this to be true.