Amateurish, those issues have already been addressed. Think of the reasons why maternity leave and paternity leave are given. Then think of the 1 difference between when a lady has a child vs. when a man does:
When a woman becomes a mother, she pushes the baby out of her fanjo. Unless you didn't realise, men do no such thing 
Sure, you may find companies wanting to sweeten a benefits package through extra pay to tempt from competitor organisations. You may also find companies trying to keep onto their own staff by giving this bit extra. Or they maybe want happier employees who will do more overtime if they are flexible in their benefits. Better work/life balance. Whatever.
The government will encourage this in order that more families bond, have more stability, greater responsibility for offspring by fathers (so less caring onus on women), as long as they balance that against the direct economic cost of sharing that allowance and going into paternity leave.
But there's a medical need in the majority of cases for women to recover from the birth. Isn't it the law in France that you cannot go back to paid employment 2 weeks after birthing? I have no idea if there's a similar law here.
But whether you agree that medical "need" to be 2 days, 5 days, 5 weeks or 5 months is by the by. The fact is that almost without exception a woman requires a recovery period after having a child. A man needs no such thing.
And this is reflected in the difference in renumeration between maternity/paternity pay and where it comes from (employer vs. government). It's a basic medical need vs. "things we do to keep people happy".
That's why companies often have the stat min for maternity leave. It's not needed to be longer, medically, it's just nice to offer your employees, for all the reasons previously given.