I've heard it asked in mysterious tones, 'have you ever seen a baby pigeon?' The implication being that maybe, just maybe they don't exist. I dismissed this out of hand. After all, I've never seen a baby eskimo, but I assume they procreate much like other humans.
And, wouldn't you know it, I've been right all along. The picture below settles this debate once and for all. You've all now seen a baby (or juvenile, at least) pigeon, and it turns out that they are freaky. That probably explains why their parents keep them out of sight.