"Most women find that babies are quieter when cradled in the left arm, and yes the thought is it's easier for the infant to hear the mothers hear beat. i suspect lefties have a harder time of it, since there stronger hand is engaged hold the baby, and not free for other tasks. "

I've never understood why the dominant hand would be stronger. I'm right handed, and because of that my left arm is stronger. I carry things in my left arm (including babies) to keep my right hand free to "do stuff." As for heartbeats, my kids seemed to prefer smack in the middle of my chest.

(btw, how do you get the quote you're replying to to show up in a different color?)