It is a difficult one.... Nobody wants to turn away genuine clients, but at the same time we all have to be sensible and not expose ourselves (ahem) to difficult situations. My view is this.....
If you are concerned about seeing erections, you have no business waxing male nether regions - leave it to a therapist who isn't bothered, and everybody wins.
If the first thing a man says to you on the phone is about erections, I doubt he is a genuine client. Genuine nervous clients tend to ask how long hae you been doing this, where did you train, does it really hurt etc.
I don't think anyone should be forced to perform treatments they are not comfortable with, but I think the employer has the right to question this at the interview stage and react accordingly.
So in a nutshell, if you don't want to do it, don't! But as someone said earlier, don't be surprised if your male clients wander off to another salon that does it all (ahem - I'm clearly channelling Frankie Howard this evening).
J