My 17 year old son is dating a 22 year old young lady, I have no problem with it but her parent's do. They are afraid that she will get into trouble? Is it legal on her part to date him?

Yes. She can legally date the 17 year old if his parents give permission. The age of consent is 16 in Ohio. The age of majority is 18. Your son is still considered a minor living under the authority of his parents. The young lady would not likely be arrested for any sexual based offenses; however, she could get into trouble if she contributed to the minors delinquency. For example: contributing to his truancy; or, if she were caught drinking with the minor or buying the minor alcohol or cigarettes. They do not share equal responsibility under the law. She is an adult, he is a minor.