[zimablue]

But women don't have to have children, in fact it would be much better if they didn't. You write your post as if it's all miraculous conception.

Women can make a choice to do something that will impact their career negatively. Men don't have that choice.

People who don't intend to have children subsidising people who do (who are on average already richer and more privileged) is deeply messed up. This only makes sense from a very narrow middle class upper-echelon-gender-equality is the most important thing in society lense.

[jvvw]

But employers know that you might have children and if you are a woman that you will have a certain amount of time off work as a result. So they might choose to employ a man instead even if you don't plan to have children yourself. Obviously illegal in many jurisdictions but extremely hard to prove.

[zimablue]

This is more of a problem of our current system of maternity leave being company funded rather than publically funded which would actually solve this problem overnight.

[michaelt]

  People who don't intend to have children subsidising
  people who do (who are on average already richer and
  more privileged) is deeply messed up.

Assuming you were born yourself, aren't you opposing something you yourself benefited from?

[zimablue]

It sounds good but it doesn't actually hold up...

So if being born means that I have to approve of any measure which causes more births, then logically I should be in favour of for example reducing contraceptive programs in Africa, etc.

Being born doesn't automatically force you to support population increase or be a hypocrite. Even if you had a moral obligation to maximise (total number of people that will ever live), then that number is probably larger (because of humanity surviving into the future) if we drastically cut population in the present.