Men can raise children, but cannot get pregnant or breast feed. Going through that cycle with potentially multiple children is a big time investment that cannot be delegated to men.

Beyond that, yes, men are perfectly capable of performing child rearing tasks. Note, of course, this does not negate the argument against a two income family. Having a society where one income can support a family means fathers can devote themselves to raising their children, and so can mothers. Or alternate roles. Or one full time career and one part time career.