Sperm Donors Responsible for Child Support?

Here’s an interesting one. If someone donates sperm (through any means) for the purpose of impregnation, should the donor be liable for child support? From UPI:

An Illinois woman said in court the father of her twins should pay child support even though the man who donated sperm claims he didn’t plan to become a dad.
Cook County Judge Thomas Kelley heard testimony from Christin Harris who said her ex-boyfriend was living with her and had proposed marriage.
Michael Wilford only admits to dating Harris and agreeing to be the in-vitro father, but claims he was just doing it to help a friend with a goal of being a mother, the Chicago Sun-Times reports.
Wilford said he was out of town on business most of the time Harris claims he was living with her, including the day he allegedly proposed.
He also said Harris tricked him into signing papers establishing paternity and responsibility of fatherhood — like child support.
When the trial resumes in August Wilford will testify why he donated the sperm but didn’t think he would be responsible for the twins.

Based on what has been reported here, it’s obviously a case of he said-she said. However, the underlying question becomes significant: If a man sells or donates sperm through a traditional sperm bank, might he be held legally responsible for child support at a later date?