Aside from funny jokes, one of the more annoying things your colonist just won't have kids, so how do you fix this?

1.Click on a colonist and hover over the three stars That's their Comfort it needs to be above 70 for the colonists to even attempt to have children.

2. Once you know what they need, build the appropriate buildings, and don't worry that they say, there's nowhere to shop when you built a shop and it's staffed, they just haven't visited it yet that day.

3.Build an Infirmary it lowers the comfort level need to have kids to 55.

4.Click on the dome its self and check your childbirth policy "The woman with a heart in here head icon" and make sure you didn't turn of childbirth somehow. you can also see if your colonists are generally attempting to make a kid from this policy as well.