Does a defender otterbox protect my iPhone 4s from steam?

I have a defender series otterbox on my iPhone 4s, will it protect my phone against steam if I have it in the bathroom while I shower? I've looked online and it said that it wasn't technically water proof, but it did protect it against water somewhat? I don't want to risk the sensor making my warranty invalid, so I was wondering if anyone knew if it worked or not.

Added (1). I like to listen to music while I shower, so that was why I would have my phone in the bathroom sitting on the sink or something

No it will not protect against steam or water. The defender is open on the back, so you can see the Apple logo on the back of an iPhone. Water can flood right through that. There are rubber caps that protect the dock connector and headphone jack from dust, but they are not water tight.

The only iPhone case that can protect your iPhone from water is "Life Proof". Www.lifeproof.com

Curious, why do you feel the need to have your phone in the bathroom when you shower? That text message can't wait… 10 minutes?

Its not made to be any other proof but shock proof protection to the whole phone. But try covering the phone with some towels before you shower