I'd just like to add that although I replied to your post I wasn't offended by it as such. Your OP suggested some people shouldn't be anywhere near parenthood for the good of society (and no doubt themselves) and, in some cases I agree.
As I went on to post myself, I realised I shouldn't be anywhere near parenthood either, so chose not to inflict myself on innocent children. My issue with it is more about who decides who should and shouldn't have kids, and on what criteria. I self policed, and I do often wish many others would too at times.
I certainly understand where you are coming from regarding criminality and antisocial behaviour. I grew up around certain families that were a nightmare. The kids were feral, and now they've grown up (but not matured) and had kids of their own. Every single one of them now scream around on stolen scrambler bikes, deal drugs, burgle and have access to guns. Police have been well aware of them since the 1980s and are still dealing with them and their growing army of offspring today.
Sadly, this city is full of families like that, as is this country generally. I just wish these people had the self awareness to realise they aren't up to parenting. Unfortunately, society is set up in such a way that it spawns people with these mindsets. Society itself is screwed, so it spawns dysfunctional cultures and individuals. Their offspring often, but not always, then carry the baton, and so the cycle continues...
I've seen you post here for ages. You are clearly a good and genuine guy. I understood the general thrust of your OP and was not offended by it. I agree, some people (in their current circumstances) maybe should not bring children into their world. The wider subject itself often veers into some pretty dark territory though when discussed.
An easier and more moral potential solution would be to just harshly punish people for anti-social or violent offences.
As Drinks Sangria said, "I don’t hold many right wing views, if any, but..." for me it's much tougher sentencing for those convicted of violent or persistent anti-social crimes.
To follow on from that:
The 'three strikes' system of punishment has a lot of merit, to protect society from the impacts of persistent criminals. I know in the US it has massive flaws, but the broad idea is, IMO, sound.