I have 90 in my population and I clicked on some villagers and it says "worried about housing". I do not seem to be able to build more houses. Also, I have seen in the screenshots before buying the game that the total population on the top left hand corner is like 400+ or 500+. I have also read that some players can make like 900+ babies in some few hundred hours. I have fully researched every tech and solved all puzzles but cannot make more babies. Please help.

I was wondering the exact same thing - I have solved all the puzzles, bought all techs and stopped at 90! There are no more spaces for scaffolding that I can find. I keep dropping my builders all over the place thinking that that should help, but nothing!

The maximum village population is approximately 90. Please see this thread for an explanation.