I have to jump in here ...
Men's hairdressing is just as exacting as ladies hairdressing. In my opinion a ladies hairdresser can become a more than competant men's hairdresser, but the opposite doesn't work. However, gent's hairdressing in it's own right is a quite exacting skill. You need to be familiar with using clippers and scissors on gent's hair, eyebrow timming, ear trimming/waxing, beard trimming, nasal trimming, etc.
If you're going to offer a gent's service you will need to offer a comprehensive one. We started off doing gent's trims and found our clients needs went as far as full on wet shaving, hot towels, Indian head massage, etc.
Think very hard before yoiu get into this unless you can provide a full service. Can you do it?