On the other hand, there's a large drawback: you can't turn it off. So there are a number of minor advantages which are easily dismissed if you manage your pregnancies correctly. You can also attempt to engage in eugenics and make extra awesome people. This is true, but you can produce more people faster and more reliably through pregnancy by having just a couple women pregnant at a time. The radio room can bring in a dweller in a couple hours, whereas a child takes 6 hours.I've actually found it to be much more effective at increasing happiness than the radio room. It's important to note that procreation raises dwellers' happiness to 100%, so pregnancy raises happiness as well. I haven't found this to be true in practice. Again, this is easily manageable by not having too many women pregnant at once.
This is easy enough to manage by not having too many women pregnant at a time, and not filling a single room entirely with pregnant women.