I would also add that we do often forget that having children is the natural default position of having Sex (obviously excepting those who are sadly infertile)
. When child allowance was introduced oral contraceptives were not available, abortion was illegal, and many couples relied on withdrawal method. Not very reliable. My own mother had an abortion after her third child , she was mentally sectioned at the time. Under the law it was illegal - they wrote it down as a D&C . Don’t ask me why my dad thought having sex with his severely unwell wife was a good idea.
Add to that until 1970s many women were forced to give up higher paying jobs when they became pregnant or even married. Sure, low paid and often insecure labour was there for them , but women paid the price , not men of their lost career. I’d like to say that has ended with equal pay act, maternity leave, etc etc but it hasn’t. The “gender” pay gap exists. I experienced that live and kicking during 1990s and my pay never caught up from that all through my career. My pension is now impacted by that.
Couples could not always plan their families and child ALLOWANCE was away for all mothers (as default) to ensure they had some basic cash to pay for children needs irrespective of how generous their husbands were with housekeeping , given many had given up, or taken pay freezes as a result of being mothers this was a small amount of recompense to cover their childrens needs.
Whilst we do now have a better ability to plan our families, there are still a minority of people who suddenly find themselves pregnant even in shitty financial circumstances. The vilification on MN about people who have children in poor circumstances in horrendous on some posts. It’s almost as if you have to decide to get pregnant if you are having sex, not that you have to decide and take action not to get pregnant and, yes, that sometimes does not work out.
Child Allowance went a little way to help costs for families in proportion to family size. It is a complete myth it enabled families to have more children, the 2 child limit was disgusting, horrific and failed to acknowledge basic biology - certainly it stank of male entitlement of sex but magically no babies. Putting blame on mothers for additional children.