Women do make less then men, but that doesn't have much to do with IQ since men and women have on average the same IQ. Women tend to not be as assertive and as a result don't ask for raises as often. Plus, women take more time off to raise a family. But back to IQ and criminality.

One's IQ is connected to race, ethnicity and environment. When one is developing as an infant and child: abuse, lack of nutrition, neglect, or damage to the brain can negatively impact IQ. Being breastfed and not being abused adds to a child's IQ (can positively impact IQ by one standard deviation), but the bottom line is one's IQ is limited by genetics. For example, the height of someone who ate healthy and got plenty of exercise as a child, is still limited by their genetics. Why wouldn't this also apply to mental aptitude? One can argue that crime is linked to poverty and not IQ, except in places like West Virginia where the population is white and extremely poor, the crime is relatively low. If you don't think IQ and aggression are linked, you should consider visiting a prison sometime.

I'm not saying every low IQ individual is prone to crime or that there aren't smart people from all races and ethnicities. These are averages. There is a bell curve as JP has explained in the past. Interesting topic one could go on and on about. I recommend looking up the IQ of different countries then compare them to their crime rate. I understand that many of these low IQ-high crime rate countries don't have access to the best food/use violence to discipline children which negatively impacts their IQ. Plus, many of the smartest people migrate to nicer countries which lowers the averages.

IQ has nothing to do with aggressive behaviour.

Unfortunately for those who wish to deny IQ (sometimes known as ‘G’ for general intelligence) is real, the data and the science continue to pile up against such beliefs. In fact, studies repeatedly confirm the reality of IQ and the connections between a variety of both positive and negative life outcomes and intelligence. Not only do studies of the general population support the reality of IQ, but even studies specifically conducted inside prison systems confirm those claims.

For example, studies consistently reflect the fact that chronic or repeat criminal offenders have a lower average IQ than non-offenders. This is true among both juvenile repeat offenders (who average about 92) and adult repeat offenders (who average about 85). IQ tests are normed for a populace to 100. Every few years the tests are re-normed due to IQ drift, which tends to be upwards (commonly referred to as the ‘Flynn effect’). The 15 point difference between the norm for the general population and that of chronic offending adults is known as 1 standard deviation.

More evidence comes from a study conducted in the Texas prison system which found that more than 20% of criminal offenders had an IQ below 80. IQ’s at such a level begin to seriously impede a person’s chances at life success and it is thought that a life of crime then becomes an alternative (dangerous and risky) path for such persons. Additionally, those who have IQ scores around 80 and below have significant problems in balancing short-term vs long-term desires. This is sometimes referred to as the ability to delay gratification and is related to time-preference (‘I want what I want and I want it now by any means necessary’ vs ‘I want X but will work slowly, methodically, and legally or morally to attain it’).

This is not, however, to say that those of moderate to high IQ do not commit crimes. The presumption here is that those of higher IQ tend to commit crimes which they are able to conceal or are harder to detect for a host of reasons. Still yet, chronic offenders do tend to be involved in far more physical crimes: burglary, assault and battery, car-jacking, drunk-driving accidents, homicides, and the like. Much of this is supported in the study linked below:

http://criminal-justice.iresearchnet.com/crime/intelligence-and-crime/3/