If there were no written contract in marriage, would no one be responsible for their children?
Are you also meaning to say that, without a written contract, the guy is off the hook for support? His act of having the child with his wife (and vice-versa) is the same as a promise to support the child — to follow through with a responsibility that is presumed in the act of reproducing children.
I’m saying that without ‘a writing,’ misunderstandings about what has been agreed to are almost inevitable. The subsequent arguments cause animosity and often result in a refusal to abide by a court-ordered settlement which is viewed as unfair. By having issues like custody, support levels, etc. discussed and agreed to in writing *before* martial problems arise, the chances that the settlement will be viewed as fair and binding are increased.
We wouldn’t dream of going into business with someone else without a written partnership agreement, because we know that we’d be asking for trouble. However, we enter into the more serious business of procreating without even a word about supporting offspring, only a promise ‘to love, honor, and obey’ our spouse. What has been promised is strictly a matter of opinion.