The media has taken largely scientific evidence and helped to promote a social misconception of evolutionary theory. Through headlines like "The Selfish Gene", "Cheating Husbands and Evolution", "The Slut Gene", and others, the media attempts to frame our behavior in terms of our evolutionary physiology, and in so doing, provide a "scientific" excuse. Men cheat because promiscuity was (is) the best way to spread their genes and thereby continue their line. Women love their kids because it was (is) their psychological need to protect their genetic line. Young women attempt to sleep around or engage in reckless sexual activity because it was (is) the best way to attract a mate. Teenagers engage in risky behaviors like drinking, drugs, and sexual promiscuity because they are evolutionarily programmed to take risks for the good of the tribe. Unfortunately, framing human behavior in 2011, in terms of our survival as a species thousands of years ago, misses the point. A specialized gene has evolved in certain people that make them alcoholics, drug addicts, and violent.
David Dobbs explains the different between what evolutionary science has found, which are traits, and the tendency to explain away bad behavior, in his Wired article, Enough With The "Slut Gene" Already: behaviors Ain't Traits. He explains that there are certain genes that predispose people to certain types of risky or unethical behaviors, such as sexual promiscuity or domestic abuse, but that people are also influenced by a multitude of other variables, including environment, emotional state, traumatic experiences, and chemical imbalances. There's also the fact that, not to get too religious about the point, we are creatures of sentient and conscientious free will. We have choices in how we behave, the words that we speak and the actions that we take. Human beings have evolved an incredibly complex neural network that has increased our decision-making capacity beyond that of simple impulse and reaction. We have the ability to over-ride our traits with our behaviors. Not every teenager speeds down the interstate, weaving through traffic. Not every man cheats on his wife and not every young woman feels protective custody of her children. Not everyone with the "alcoholism gene" because an alcoholic, and many people without that gene do.
It's an interesting, and more often convenient, way for us to understand our urges and our behaviors; to apply them to a kind of unyielding and involuntary genetic "essence" within us. However, these genes, these evolutionary traits that predispose us to certain types of behavior (in a very distant and obsolete context), are not an inevitability. In fact, their influence on our behavior is often overstated when you look at the other circumstances impacting us. Instead I would consider them like a human coccyx (tailbone), or appendix; holdovers from a bygone era in our evolution that have no particular use to us in the present. With some force of will and management of our situation, traits are simply traits, and behaviors are our own.