This is a statement that researches have long sought the answer for, it all boils down to nature versus nurture. Is there a clear answer? I can honestly say now that I do not believe so, after evaluating both sides I see that nature and nurture seem to play an almost even role. Therefore, I do no think it is fair to determine this question with a yes or no answer, instead I hope to present the facts and allow others to make a judgment based on those. When beginning my research I had the advantage of working with top psychiatrists in my area to try and determine the cause of criminal behavior, and I realized very quickly that there are two very convincing opposing sides and no clear evidence that either is correct.
I would like to start with the argument that criminal behavior is not biologically determined. To be biologically determined you could say that this person had a mental illness that drove them to commit these felonious crimes. Many people do not even believe in psychiatric illness none the less that it can drive behavior. I work on 552 evaluations, which are essentially people who plead not guilty due to reasons of insanity and there is a team of us that meet and evaluate the legitimacy of those statements. We have a team of psychiatrists, psychiatric nurses, and medical doctors with no affiliation to the psychiatric field. One of those medical doctors constantly says to us that "a brain can be diseased but a mind can not, because the mind is not a physical organ". He believes that blaming mental, emotional, and behavioral problems on mental illness allows a person to reject free will and personal responsibility for their actions. To him the words psychological and biological are not synonymous, so therefore you can't be driven to do a crime on a mental basis.
There are also those that say criminals are made from bad upbringing, that nurture plays a key role in the development of the criminally minded. Many believe that if you are brought up in an environment that is abusive, neglectful, or very low on the socioeconomic standpoint that you don't stand a chance in life to become a healthy satisfied adult. There are many different psychologists that have developed stages of development and what must be met in those stages before you can move to the next. When you don't meet one of those stages you can't move to the next and don't develop the skills you need to be a healthy adult. The first stage in Erickson's model is Trust vs. Mistrust which occurs from birth to around 12-15 months. You develop trust with consistent nurturing care and hope, but basic mistrust with abuse or neglect. If you become a person who lack trust and don't care if others will trust you what is to say that you will not ultimately commit a crime due to a lack of care for others. Each stage you move through has a goal you need to meet, if you do not meet that particular goal more and more personality problems and lack of care for others develop.
On the biological standpoint there have been some recent developments that have shed a lot of light onto the criminally minded. There was a discovery in the 1960's that an extra Y chromosome was present in a lot of criminally minded people. This is a very rare condition in the first place so to be able to take the rarity of it and find a group on similar people who had it was remarkable. The biggest problems usually have to do with personality and behavior. XYY boys are often (but by no means always) more aggressive and less tuned in to the feelings of others than their counterparts. Another sobering study found that the frequency of XYY among institutionalized male delinquents was 1 in 35! Taken together, these studies indicate that an individual boy with XYY syndrome will probably not have serious mental, behavioral, or criminal problems -- but that his odds are 24 times more likely than those for an XY boy. These...