* stuttering has a large genetic component (at least 50%). * you can't acquire stuttering by hearing someone else stutter. Your brother did not start stuttering because he heard you. * you need to talk around your baby. The more you talk to your baby, the more words you use, the better their lingual development will be. * your fear of him stuttering or him hearing you stutter is likely going to be a bigger issue than the stuttering himself. Either talk to a speech therapist and get more comfortable with yourself about it, or figure something else out. You don't want to be apprehensive or insecure everytime you talk to your baby because you might stutter.