when can a baby start having a Walker?? my son is 5 months old and my husband is telling me that he's to young for it…

when can a baby start having a Walker?? my son is 5 months old and my husband is telling me that he's to young for it and it will give him bowed leg. what's the difference between a walker and a saucer/bouncer. my son has a saucer/bouncer.