How much money would you think would be fair to pay for your childs food, clothing, shelter (mortgage and utilities) etc.
Not a slam, just a mathematical question. What would be the minimum to keep him alive and what would be the max you’d be willing to pay for slightly better quality of life for your child?
The question is irrelevant. No matter what the figure is, the point is the mother of the kid is morally responsible for 50% of the cost of supporting that child. Your buried assumption that the father should be wholly responsible is sexist nonsense more suitable for a meeting of the cows of NOW.