It's probably none of these (well perhaps having lots of bath toys might swing in your favour). What makes a great child-friendly bathroom is about making the bathroom accessible to children so they can use it independently.
You might think that tiles aren't especially child-friendly. Floor tiles especially as they are hard and can be cold on little feet putting them off using the loo in the night. But unlike carpeting they are waterproof which is great when your little darlings are having a water fight with the shower spray. Fully tiling your bathroom with easy to clean ceramic tiles can be the first step towards creating the ideal child-friendly bathroom. And you can always add under-floor heating or mats to make it warmer.
Step On Up
Bathroom fittings are fitted at a specific – adult – height. You could create a miniature bathroom complete with child-sized toilet and basin but most people need to adapt what they have. Providing a step-stool – or two – is a really cheap way of making your bathroom accessible to your kids. If space allows having two means you can have one by the loo and one for washing hands making it more likely they'll actually get washed.
Since fitting one of the tiny loos that nurseries have is probably not feasible the next best thing is to fit a family toilet seat. It simply replaces your existing seat with one that contains a child-sized insert. No longer will your child have to balance on the edge or remember to put the training seat on (and who can find a place to store it anyway?). All they do is lift the lid – just like mummy and daddy.
Keep It Handy (For Your Kids)
Often bathrooms have limited storage at child height. Baths are blocked in to hide the plumbing. Wall space is taken up with awkwardly shaped fittings or radiators which means most of the storage is on shelves out of reach of little fingers.
Of course you need some high storage to keep cleaning chemicals, medicines and beauty products out of reach but if you can find somewhere to keep a basket of bath toys, their toothbrushes, or a few towels lower down you will be making your bathroom much more child-friendly.
A great place that is often overlooked is below the basin. In a fully fitted bathroom you may have drawers or cupboards but if you have a pedestal or wall-hung basin the space below could be wasted. There are several designs of under-basin storage available on the market, such as cupboards that wrap around the pedestal or wire baskets that can slot in down below. All of these will allow you to give your children somewhere to keep their bathroom stuff where they can reach it.