I voted babies because I'd really like to see them be able to be removed from the bassinet. Being able to take them off of your home lot with strollers or carriers would be amazing, plus it'd be much better if they were treated like an actual sim, rather than an object. There is so much potential for babies, and I don't think that there are many people that understand that some do play with the long lifespan or with aging off from time to time, like me. Babies can stay a baby for literally as long as you want, and new updates for them would be all the reason to make that life stage longer in your game. Teens and young adults really don't change that much in real life either, maybe just in body shape, voice and style, so I don't think that major distinction between the two of them are really necessary. I mean no one complains about young adults and adults being too similar; I've even mixed up those two life stages before. You tend to not change as much throughout your adult life until you reach that elder peak, so I think that making babies more a part of the family, and with more interactions would be much more worthwhile. :)