If your villagers have finished that first hut that was partially built when you started the game, they will be able to grow to a population of 15 before you need another hut. Sometimes, if there isn't at least 400 food in the bin, they will be reluctant to make baby villagers. Sometimes they don't get along. Watch for messages at the bottom when you try to make babies - that sometimes explains things - but you might just have to be persistent. It can take a dozen or more tries before a baby is produced, especially early in the game.
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Barbara
Unicorn
Last Day of Work