If you and your wife are having a child that needs special care to be born into this world and need a special Doctor with special skills to deliver the child, you would not expect that Doctor to demand a share of that child's earning for the rest of its life. He was using his special gift to do his job, no doubt well paid for it. If an artist has special talents to sing but can't write, why would he/she demand income from the talents of a writer that supplies him/her with a product he/she needs to display his/her talents. We are all given different gifts and talents and are expected to use those gifts to help mankind, not steal another's gift just because they are in a position to do so.