Why would someone want to make a kid with someone they are not really attracted to?

There was someone in a high position (department head) where I worked who was said to have married and had a child in order to receive an inheritance from his father, who was wealthy. He told him if he didn’t marry & have a child he would be cut out of the will. So he had one child, he was getting up there about middle-aged and developed Parkinson’s disease and died before he could get the inheritance.