Can your mood really affect your baby's behavior when he/she is born?

Some people tell me that your mood or attitude can affect your baby's personality or behavior when he/she is born. For example if you have a positive attitude all the time your baby is likely to be a "happy" baby. And if you have a bad attitude and are always angry, your baby will always be fussy and cry alot. Does anyone know if this is true? Or is there any experienced mothers actually know this to be true?