While there are a few valid points raised (child custody), the overall theory sounds as silly as the nonsense spouted by the right when they talk about discrimination against white men or Christians in the US. You would have to be living in a cave to ignore the ongoing discrimination against women in the workplace, who make less for the same work. Women also are much less represented in corporate management and the last time I looked at Congress or many First World parliaments, women are severely underrepresented.
You might not have realised it, but men are being oppressed. In many walks of life, they are routinely discriminated against in ways women are not. So unrecognised is this phenomenon that the mere mention of it will appear laughable to some.
That, at least, is the premise of a book by a South African philosophy professor which claims that sexism against men is a widespread yet unspoken malaise. In The Second Sexism, shortly to be published in the UK, David Benatar, head of the philosophy department at Cape Town University, argues that "more boys drop out of school, fewer men earn degrees, more men die younger, more are incarcerated" and that the issue is so under-researched it has become the prejudice that dare not speak its name.