Actually I'd heard it was the other way round - more likely to be sick with girls. But that wasn't borne out by my experience. Had no MS whatsoever with DD. Suspect it's an old wives tale but happy to be proved wrong!!
No experience of this myself as I have only had a girl and I didn't have any morning sickness but I know a friend of mine had a girl and she suffered with morning sickness terrible for months. She is now pregnant with a boy and she says she hasn't really had any morning sickness so I think it may be just an old wives tale to be honest
I had a boy nearly 14 years ago and was as sick as you could get, now i am 20 weeks pregnant and carrying a boy again so i found out today at my scan, i had been as sick as a dog again and that was right from when i found out i was pregnant at 5-6 weeks, day and night you name it i was being sick. Som nights it was every hour through the night, now it has calmed down and maybe only sick once or even none some day's x