I am a person of great skepticism and I almost never believe anything unless I experiment it by myself but I am convinved that human behaviour can be explained in plain scientific terms. Genes regulate many aspects of our personnality but the extent to which the gene effect will be measured involves social interactions and other things that cannot be explained in biochemical/genetic terms.
Yet, bot aspects of who we are are connected through genes, mind, conscience, perception, stress etc.... (May I propose a very good podcast about the effect of a crowd on human behaviour? CLICK HERE to access it) and the scientific community seems to be reluctant to create relationships between Science and Human Nature. According to an article from the Skeptical Inquirer there are two reasons that explain the distance observed between "hard science" and "social sciences":
"There are two overly concise reasons for the segregation of social science from biology.In an interesting intellectual twist, the author (Lionel Tiger) refers to a set of behavioral "vitamins" that explain our needs, when these "vitamins" are missing, problems seems to emerge. Curious about the nature of these "vitamins"? Read HERE
The first has to do with a broad allergy to “reductionism”—in effect, trying to explain a social phenomenon by a physical or genetic cause."
The second and perhaps more significant reason for the segregation of the two sciences has to do with the appropriation of some biological and many nonbiological materials by various fascist groups, especially the Nazis. Consequently, there was plausible and understandable suspicion of attributing to genes any major social or cultural phenomena."