Oh FFS people! This is 2014 - decent workplaces recognise that people have lives outside of work.
Obviously you carry on if it is a bit of a sniffle but if a person is genuinely really ill then no they shouldn't be looking after small children.
Both dh and I have had "martyr maladies" in the past. Where you get a bit ill but are really busy at work so soldier on and then end up really ill and taking off more time than you would have done to start with. Dh ended up in hospital for 3 days because he was "too busy" to spend a couple of days on the sofa watching crappy telly.
As a result we are now sensible and if ill we take the time we need.
The way we work it is that we are honest with each other and are confident that neither "plays" on illness.
The only time I was ill during my last maternity leave was about a year ago when I had a raging case of tonsillitis. Couldn't get out of bed. Ds was 3 months so I reckoned I was ok to look after him (he just lay in bed with me and I provided him with open access to the milk. He thought it was his birthday). But I couldn't look after dd (then 3). So dh took her to pre-school went to work for 3 hours, picked her upm, brought her home, fed her, then worked from home while occasionally changing the tv channel, fixing dolly's broken leg, opening the box with the crayons in etc. he had to work a bit that evening but all in all we coped. By the next day I felt better but not well enough to do the pre-school run so he did the same thing but when dd got home I supervised the telly channel changing, dolly fixing and crayons from the sofa. By day 3 I was well enough to do the pre-school run.
Obviously only worked as he works near home and Can work from home. But it's part of the package. Two WAHP and you have to take time off when child is sick. A SAHP and the other one has to take time off when they are ill. It's still a huge gain - adults are rarely ill anywhere near as much as the average toddler in nursery.