Argument: Mothers on maternity leave are not working, therefore they have no right to be paid
People get paid to work. If a mother is not working, then they are not doing their job and therefore don't deserve to get paid. It is not right to give all mothers paid maternity leave - that is the mother getting full pay for not doing anything, which is unfair. Small businesses especially can't afford to pay people who are not working, and often need to hire someone else in the person's absence, costing more money.
All mothers should have the right to maternity leave when necessary, but it does not need to be paid maternity leave. Getting paid for not working is not fair and once the person gets maternity leave, it is an unfair and unnecessary luxury to be getting paid.