I have a 10 month old at my house. When he started crawling I bought a GunVault mini with the standard 4 finger combo. You can program whatever combination you want - kind of like a cipher lock. You're choices aren't 1,2,3 or 4 - you can do 1+4, 2, 3. With that I figured the odds of the kid accidentally mashing the buttons in the right order was zero. I'm a little skeptical of the biometrics stuff - I'm sure it works fine, but to me it seemed like one of those things that would only fail when you need it to work.
Bottom line: it'll keep the baby out, it's a little bulky, but I just have it sitting on my nightstand. I'm happy with mine.