I have some concerns about the study itself. Anthony Bogaert is a psychologist and professor of community health sciences. He did a statistical study and then made pronouncements about genetics and cellular biology. I find that rather odd. He is neither a geneticist nor a cellular biologist. Statements like:

A woman's body may see a male foetus as "foreign", he says, prompting an immune reaction which may grow progressively stronger with each male child.

The antibodies created may affect the developing male brain.
We are extremely far from even beginning to understand the processes involved between mother and foetus and the immuno-response. Transposons, retrotranposons, the proteome, viral fragments, introns and more all play a very poorly understand part at the placental barrier. And yet, here's a psychologist making pronouncements about the genetic and cellular biology involved? I don't think so.

Worse yet, Bogaert has a history of pushing this view. He's associated with the Clarke Institute in Canada, which has a rather sordid reputation.

I say take it with a huge grain of salt, and let the real scientists weigh in on the matter before accepting it as anything even approaching valid.