Sometimes when a man and a woman ask me to leave the room, a baby is made, and nine months later I'm asked to leave the room again. This happens frequently and it's fairly mundane. There are currently 7 billion people on Earth, and somehow we still act like this is a remarkable feat. One needs only look at Octomom to start losing appreciation for the skill required to pass a human through a vagina (you keep your Caesarean comments to yourself).
If someone at your workplace or in your group of friends announces in front of you that they're having a baby, you're going to have that moment when congratulations are delivered. Some are probably very sincere -- maybe you really think the fact that they humped successfully is cool, I'm not judging. I'm just suggesting that, for most people, this congratulatory expression is the result of being made to feel like you need to, rather than any real sentiment. Because really, what did you do? You boned without the aid of birth control and biology worked. There are life forms on Earth right now that can change sex in order to reproduce, and others that can reproduce all alone without even finding a partner. No one congratulates them, so how is your effort more worthy of praise?
Realistically, people should congratulate you when your child turns 18, contingent on the kid not being a piece of s**t. If you have and raise a child who becomes a good person and the world is better for having him in it, then you get congratulated on a job well done. Congratulating people on a baby is like praising a chef for buying beans and a ham only to have him serve you ham-and-bean-crusted turd kabobs.