Which gloves are better to use for changing a babies diaper?

Latex. They're disposable and fit better than rubber (if by rubber gloves you mean the kind people wear while doing dishes and other cleaning). Just double-check with the parents for next time: brief exposure to latex probably won't hurt her, but if she does have an allergy to it you'll have to stick with rubber gloves in the future. Or just suck it up and wash your hands very well after, like everyone else does.