"When I was pregnant with my 2nd child I remember talking to some friends about singing their children to sleep (they were pregnant the same time I was) and they looked at me like I was crazy. They said they would never sing their kids to sleep because they would scare their children with the way their voices sound. That opened my eyes. To me, the sound of mommy is the most comforting soothing sound a baby can hear, I never thought someone would be so insecure with their own voice that they would rob their child of those bonding moments of pure peacefulness just hearing mommy singing to them, A child doesn't know if you are in tune or not. Just that you are there for them and that brings them overwhelming comfort.
From an interview with songstress Candice Night, lead singer for Blackstone's Night, who do a lot of renaissance style music. Full disclosure: this was her motivation to write some children's songs and release them on CD, so people could play these at night and in the morning for their children.