Earlier quoted context omitted.
So does that mean that companies would favour women as they can be paid less?
Interesting question. I think many, men and women, are still biased against women because they believe they are catty and dramatic or are afraid of increased legal issues (lawsuits). These are obviously not reality either and it too sucks.
Maternity leave means that women effectively cost more than men for the same amount of work, in the long run and on average. This can be mitigated by laws, but cannot be eliminated without addressing the underlying social issues. And no, mandatory paternity leave doesn't eliminate it, as there are more single mothers than single fathers.
The logic is simple. Companies survive by making a profit. In order to do so, they attempt to cut costs for a given amount of work done. Currently, females on average end up spending more time on paid leave. Hence, there ends up being a bias.
And I'm not sure if it is one that can be fixed through legislation. Attempts in that vein tend to be counterproductive at best. It's more of a social issue.