I know how to solve this problem...
Pregnant men!
Oh...it is not possible.
Never mind!
I was discussing this subject with a married couple (friends) today. They have two children, one was born just last month. The husband is a very good friend of mine and I helped them move into their new home 2 days ago.
Anyways, he thinks having an "opt-out" for men is hilarious. He is pro-choice, but his wife is pro-life and they have ..... "discussions" about this all the time.
He said the only problem he sees with having an opt-out for men is if a man decides one day to say "I NEVER wanted children, but my wife/girlfriend did so I gave her one".
In other words, he said the problem was "Who is to say he didn't want children?"
His wife said pretty much what most of the women here have said "If he doesn't want kids, he needs a vasectomy."
However, she did admit that she thought more women would be much more careful with who they decide to marry/have a relationship with if they knew men could opt out and could not be railroaded (protected from deception such as the man in the OP).
They both agreed that the man in the OP should not have to pay child support since he was intentionally deceived into a relationship he did not want.
There was also a flip side to all this and he mentioned something I hadn't really though of .... he asked "Why did she feel it was necessary to deceive a man if all she wanted was a kid, couldn't she have just gone to a sperm bank ..... oh .... sperm banks don't pay child support ....."
His solution was (he said this jokingly) was that women should be given a pill when they are born that prevents pregnancy. When they want to get pregnant, they should have to fill out forms and then get a pill allowing them to conceive. He also said in 10 years he is going to invent it and he will get rich ....