@croydon - I think I read that same article. One thing that freaked me out a little is the fact that sometimes the cremaster has muscle problems, including severe cramps that won't stop. I can't imagine how painful and annoying that must be.
And the only real cure for it is to inject the cremaster with botox, or to do surgery on it. In some cases they will remove it entirely, without many long term effects.
I suppose in that case the testes just wouldn't be able to contract back up and you'd have to be extra careful of them in certain situations. Another interesting point is that they think that low sperm counts might be coming from men using a laptop on their knees. The testes can't stay cool when exposed to that kind of warmth and the sperm basically cook so that they aren't fertile anymore. It's not the kind of temperature regulation that the cremaster muscle can help with.