You will find out things about your spouse and yourself that you never knew about, but your kid will have inherited them. Some of these things are attractive features, others are not. You might have to figure out how to deal with a feature of your kid that is not attractive. Some of these things can be fixed in post, others, not so much. Some of these possibilities include genetic diseases, which absolutely no one deserves, but do happen.
Having a kid is an enormously brave and risky decision. You roll the dice and you get what you get. There's no going back.
Edit: All that said, I do not regret my decision, even though I've been exhausted for coming up on two years and so has my wife. When it's bad, it's the worst. When it's good, it's the best. You will find yourself capable of more patience and resilience than you ever thought possible.