Why were Sanhedrin members required to be husbands and fathers?
Sanhedrin members had to be husbands and fathers so they could rightly judge cases involving parents and family matters. Without that personal experience, they would lack the understanding needed to pass judgment on what parents had to deal with, according to the qualifications described.
Les explains that a Sanhedrin member had to be a husband and a father because, if he were not, he could not properly pass judgment on what parents had to deal with. He reasons that Paul must have been married and had children, since to vote in Acts chapter 26 he had to be a member of the Sanhedrin, and one qualification was being a husband and father. Les also notes that Saul of Tarsus was a Pharisee, a Pharisee of the Pharisees from the tribe of Benjamin, and therefore a Sanhedrin member. What happened to his wife and family, however, Scripture does not say.