Nature-nurture problem

The nature-nurture problem revisited in most vertebrates, early experience of certain odors, interwoven with genetically anchored developmental processes, produces lasting, often irreversible odor recognition, preferences, or avoidance. Such behavioral development often occurs during more or less defined critical windows in time. The development of responses to odors often precedes that of odor production. Neonates already orient towards odors, while many pheromones are not produced until adulthood. Even before hatching or birth, the journey of chemical communication starts in the egg or the uterus. Knowing how chemical communication and chemosensoiy responses to food or danger develop is essential in areas such as animal husbandry or human behavior. 

To what extent does variation in the activity of an inducible enzyme in vivo reflect the capacity (genetic potential) to respond to an inducer and to what extent does it reflect a difference in exposure to that inducer This is the classical nature/nurture problem wherein both factors frequently are unknown. The capability for induction in humans usually has been assessed by studying human cells in culture (26-29) rather than by exposing human subjects to inducing agents. However, some in vivo human studies exist and they confirm that intact humans can, indeed, respond to inducers. There have not been many circumstances where induction per se was tested in humans. Most in vivo studies compare enzyme activities in populations... 

The question of whether or not homosexuality is an illness k therefore a pseudo problem. If by disease we mean deviation from an anatomical or physiological norm—as in the case of a fractured leg or diabetes—then homosexuality is clearly not an illness. Still, it may be asked if there is a genetic predisposition to homosexuality, as there is to a stocky body build or is it entirely a learned pattern of behavior This question cannot be answered with assurance. At present, the evidence for such predisposition is slim, if any. The biologically oriented person may argue, however, that more evidence for it might be discovered in the future. Perhaps so. But even if homosexuals were proven to have certain sexual preferences because of their nature, rather than nurture, what would that prove People who are prematurely bald are sick, in a stricter sense of this... 

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