Things versus people.  Su et al (2009) performed a meta-analysis of studies including a total of over 500,000 people examining gender differences in interests.  Despite claims that gender differences are typically “small” (Hyde, 2005), Su et al found a gigantic gender difference in interests.  Women preferred working with people, whereas men preferred working with things, a preference that is detectable within the first two days of birth and among our close species relatives, rhesus monkeys!  To be sure, these differences were not absolute.  Not every man prefers working with things, and not every woman prefers working with people.  But the effect size was d= .93, and even if you are not familiar with effect sizes, this would make it one of the largest effects in social psychology; it is gigantic.
From Psychology Today, Lee Jussim PHD