I'm going to guess that you:
1. Don't have kids
2. Are a male (I'm male as well)
Having kids is a big decision. (I'm lucky enough to have two so far).
We (wife and I) have had to make a lot of sacrifices, both financially and at a family/career/personal level. We are lucky that we both have reasonably good jobs.
However, being pregnant is an absolute b*tch, and seeing what my wife went through, and what some of the other mums in our parents group went through - I am very dubious anybody intentionally gets pregnant only to get a few extra weeks/months of leave.
If you're a guy I suspect we probably can't know how bad it is. Let's just say that tearing or being cut down there isn't fun, and for many women it can have lasting impact on your body.
For both of you it upends your entire life - and you're on the hook for the next 18 years (at least). And not just financially, but you need to actually spend time with them - feeding them, changing nappies, reading books, playing games, looking after them when they're sick, taking then to school every day, teaching them, ferrying them to activities etc.
I have zero regrets - but it really irks me when immature people start commenting about how providing things like parental leave will encourage people to "abuse the system".
Those people were likely already going to have kids anyway, so I don't see why we as a society shouldn't support them - unless we want to deal with the demographic and sociological implications that comes with a rapidly aging population and no young people.