YABtotallyU. Someone should not go back to work after parental leave because they're trying to conceive???? What if it takes them years? What if it never happens? How long should they sit at home, trying???
If you happen to fall pregnant shortly before you are due back, should you forfeit those months' salary, that you would be able to earn before the next child is born? Just give them up and manage on no income? Go on benefits when you have a perfectly good job that you are capable of doing?
You don't 'earn' parental leave. It should be every parent's right. The fact that some employers offer a better deal to employees who've been there longer is unfortunate. The fact that women are made to feel like they haven't earned it is wrong.
It is hard on small employers, but if you can't afford to pay leave for an employee (sick leave, parental leave, whatever) then you should seriously look at whether you can afford to have employees.
And co-workers can of course feel the disadvantages to being in a team with changing personel, but that applies if someone goes on parental leave, gets sick, leaves for a better job, is promoted out of the team.... ... ... Don't dump on a parent taking parental leave as somehow being more culpable than anyone moving around in their working career.
It should be perfectly normal to take parental leave to look after small children. Part of a healthy work : life balance. Noone should be expected to plan their family around the needs of their employer. But that is unfortunately the picture of a perfect world, not reality.