One species, two genders. Yes, biologically we are fundamentally different, but what about psychologically? Is the difference between men and women all a 'social construction'? What if you give dolls to a male child? What if you treat him like a girl? What if you dress him like a girl? And what if you surgically reconstruct his genitalia so that, anatomically, he looks like a girl?
Will he be a girl?
Whether you know what the psychological evidence has to say or not, you'll recognise that this issue is political dynamite. If there are fundamental psychological differences between men and women, then perhaps some forms of discrimination are valid? Perhaps it is right that men go to work and women stay at home to bring up the children?
Of course these things don't follow, one from the other, but it doesn't stop people associating these arguments with each other. Bear this in mind while you read the Scientific American article and if you should choose to share this information with people more concerned with political correctness than scientific accuracy.
His Brain, Her Brain [Scientific American]