Actually this is normal when you start a new generation, you get either 3, 2 or 1 eggs, it is random, except when you get a pure family and you get 2 eggs automatically.
I got the idea as well that you can have from 1-3 kids in next gen blended family. :x I'm on my 2nd gen so... this hasn't happened to me but let's see if it does. I don't think it's anyhow unnormal, so no; you don't need to worry.