Being as I am in the medical field, this would be my advice. Ask your friends who they go to for their physicals. To ask for recommendations would give you the chance to look he or she up online and get a better idea of things. Prostate exams usually start at age 50, so you should be fine. But remember when you turn 50, ask for lube!
I used to have a female GYN thinking I would be better off, but one time I had to see her ASAP and she wasn't on that day, so I had to see her partner who is a male. Turns out I liked the male so much better. I found females tend to compare themselves to other females, where as a male will tend to be more sympathetic. Needless to say, I switched. In the end, you should feel comfortable with who your doctor is and trust him. You know the saying.."Doctors bury their mistakes." This is true. And if something feels off, and any Doc says you are fine, never stop investagating. Nobody knows your body more than you. Too many times I have seen medical mishaps due to false negative testing. Please don't let this be you. And if you are 50, get that colonoscopy. And don't think you don't need one just because colon cancer doesn't run in your family. More colon cancer deaths are of those who think this! True, colon cancer does run in families, and those who are aware get tested and many lives are saved. It is more those who don't think it so necessary are the ones who often find out too late.
Good luck to you on your appointment!