Question

Explain how genes and hormones influence behavior. How do jeans and hormones influence someone being left-handed over right handed? How do you jeans and hormones influence sexual orientation (someone being homosexual vs. heterosexual)? What does the research say? How are these theory similar? What are the ethical issues?

Answer 1

Genes and hormones constitute two strong biological factors which control behaviour. They provide support for the nature point of view that is, human beings are inherently predisposed to think, act and function in a particular manner. The transmission of certain chromosomes or genetic code in the form of DNA from one generation to the next generation controls factors as wide as intelligence, the vulnerability to disorders such as schizophrenia, and mutation of chromosomes or chromosomes abnormality at the time of birth such as that implicated in the inheritance of an extra 23rd chromosome in the incidence of Down’s syndrome in the offspring, constitute evidence for the multiplicity in the way genes control human behaviour and mental processes.

Similarly, the optimal level of hormones secreted by the different endocrine glands in the body is a necessary condition for adaptive behaviour and physical health. However, abnormalities either in the form of oversecretion or undersecretion of vital hormones such as corticosteroids, ACTH, or the Male sex hormone testosterone and the female sex hormones- estrogen, progesterone and oxytocin, is found to have adverse effects on cognitive, physiological as well as psychological health. For instance, an excess of testosterone in females is associated with appearance of secondary sexual characteristics such as increased growth of facial hair, hoarseness of voice, irritability and greater tendency towards aggressive behaviour. Moroever, an excess of corticosteroids which is secreted during conditions of stress, prepares the body for fight or flight response against potential threats by stimulating the activity of the autonomic nervous system and increasing heart rate, respiration, etc, however, it is also found to trigger greater sexual drive in the individual.

While there is a wide array of evidence which supports the role of both genes and hormones in human behaviour, the evidence in the case of a few areas such a study those pertaining to sexuality is at best dubious. For instance, sexual orientation is deemed by many genetic researchers to have a stronger biological component than a social choice. testosteron-deficient males have been shown to have marked decreases in a subset of their masculine-typical behaviors and a trend toward a more feminine-type of behavioral profile. That is, males are hypothesised to achieve fewer intromissions and almost no ejaculations if they have low testosterone.

Furthermore, Kallman’s syndrome in males is shown to have a strong genetic and hormonal basis. The damage at Xp-22.3 disrupts a specific gene (13, 14) whose damage causes low testosterone levels, in turn because of reduced gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Thus, an interaction of genes and hormones leads to a low libido and interest in sexually pursuing a person from the opposite sex which is associated with X- linked Kallmann syndrome.