My parents have a cat that does this every time he gets anxious. This means when it storms, when they had to fix the roof, when he sees another animal walking down the street (he is safely inside, but it doesn't matter), when too many people come over, etc.
They've torn all the carpets up, and now have tile or hardwood floors (which looks nicer anyway), and the cat is on buspar, an anti-anxiety medication. It hasn't stopped it entirely, but its helped a great deal.
Maybe they are just anxious because of the child. I know its hard with a young one, but is there a way to keep them apart?
Jess
You have quiet a problem on your hands as you will have to try and find the cause ie when did it start, is there any new people or pets come into the house, is there a stray cat visiting your house that is causing them to lay claim to their territory by spraying. You can get an enclosed litter tray that they can't pee over the edge I have found this wonderful for one of my cats who just backs up too close to the edge to pee even though we have the largest cat litter trays you can buy.
To be honest with you you may have to try retraning them once you have found the cause. That means starting in a confined area to sleep at night like the washhouse so that they have to use the litter tray and can't do to much spraying and only letting them out when you are there and can watch them.
The other things is once they spray it is hard to get the smell out and when they smell where one of them has been they will use that area again. I have used 1/2 vinegar and water to lift the smell and clean up and I guess you would know not to use bleach as cats just love this smell and will use it even more.
I have clients who had two devon rex's and had to re home their cats because of this problem and they had their cats on anti depression, anti anxiety, and happy pills and nothing worked.
They spent thousands of dollars taking them to the vets and councillors and still had to give them away because no answer could be found. The last straw was when they brought a 4,000 dollar lounge suite and the cats peed all over the sides and down the back of the cushions all within two days.
I hope you can get to the bottom of this and have a happy ending....