When I am at work, I deliberately concentrate on lowering my voice an octave or twelve when I am on the phone. I have got several offers of dates etc, and a customer-friend says I sound really sexy on the phone. I don't answer it much, so it is not a constant thing.
However, at home, or when I am not concentrating/tired, I don't bother and apparently I sound like a two-year-old who got to Mummy's phone first! MG has played back my messages sometimes when I leave one, and they are right. I sound like a small child! No wonder telemarketers always ask me if my parents are home!