You are significantly mistaken. The courts don't throw out "unreasonable" contracts people willingly agree to. You are perfectly able to sign rights away and most of the US courts will uphold that quite willingly and enforce it. In all but California you can sign away your right to be employed in the only field you are qualified to work in (non-compete clauses), only in Cali are these clauses illegal specifically because they were made illegal by the California legislature.
Now this first born clause would be thrown out for a very simple reason. It's not legal to sell babies, any clause that purports to do so is void as a matter of law. In general any clause that purports to sell people is not legal because you can't own a person in the US. This is the reason slavery contracts aren't legal even if both parties are willing.
As a general rule, the only contract clauses that will be tossed after willingly agreeing to them are clauses that are illegal as a matter of law or if you were under duress or mentally incompetent when the contract was signed. I'd happily sign a contract with a first born clause because there is no way such a clause would be upheld, the other stuff not so much.
The courts don't care if you read the contract or not, you signed it, you will be held to it. And clicking X is signing it in the US.