My husband doesn't want boys calling our 13-year-old daughter on the phone at all. He will allow her to email back and forth with boys, since we will be able to read their messages to see if they are inappropriate. I think he's being too overprotective about the telephone use, and my daughter does also, even though she has accepted the rule and not broken it. Do you think it is appropriate for boys and girls to talk on the telephone at this age?
Everybody -- especially teenagers -- need and require privacy and space. By reading her email, you are invading her privacy and space without any good reason except a suspicion. It is through her interaction with others -- boys or girls -- that your daughter learns about her self and how to relate to others. If we as parents want our children to be trustworthy, we have to trust them until they disprove our expectations. It is normal and appropriate for boys and girls to talk on the phone and email each other.
Parents can and should regulate when calls can be received, how long they can last, etc. If you keep the lines of communication between you and your daughter open, she will tell you if a caller is being inappropriate and if she can't handle it. If she has trouble handling a situation, then you can offer suggestions from your own experiences, but you want her to learn and practice these skills on her own as much as possible.
My experience with teens tells me that if you read your child's email and her diary and listen to all her calls, she will withdraw from you and find a way around your rules. I know you don't want that, so I urge you to set your expectations and trust her to behave responsibly. Stay out of her email. Give her some space to grow.