A registered sex offender admits he made a mistake 20 years ago, but he says he paid for his crime.  Now, 49-year-old Stuart Yates is suing Wisconsin Children’s Hospital because its policy prevents him from seeing his seriously-ill nine-year-old son.  Yates was escorted from the building last week.  His suit argues the visitation policy is “cruel” and it “causes unnecessary harm to families and innocent children.”  Yates was convicted of sexual assault of a child in 1998 which happened while he was at a house party where strippers performed.  He says he didn’t know the victim’s age.  His son was having surgery last Friday.