IVF is definitely relevant. It's hugely expensive. It's paid for because the government recognises the importance of children to society/the happiness of people/as a human right. Of course it's fucking relevant!
As for maternity leave. We don't have paid goverment mat leave in Australia. And every time it's brought up, do you know what the argument against it is?
"Oh, having children is a personal choice. If you can't afford it, use a condom. I'm sick of people expecting the government to fund their lifestyle choices. I didn't have a child till I could afford to support it myself."
It's the same argument! Just because you lot are used to maternity leave being provided doesn't mean it's a totally different matter. Maternity leave, like social housing, welfare benefits, public health and the rest, are paid for by tax payers money that goes into the pot and is redistributed according to the perceived social good.
"Oh, but everyone can get maternity leave/NHS services/etc so it's different". Well, no. People WITH CHILDREN can get maternity leave. If having a child is a choice and personal responsibility, why should the childless taxpayer have to fund it?
Because we as a society think it is in the public good to ensure that children are educated, fed, have their health taken care of, etc. We as a society are willing to redistribute wealth to ensure that happens.
Well, as a single-child-having, fulltime working, taxpaying, personal-sacrifice-to-ensure-a-certain-lifestyle-making poster, I'm also perfectly happy to fund the adequate housing of otherwise overcrowded and miserable children. Because I don't feel the need to punish tiny children for the perceived misdeeds of their parents.