Toddlers sixth sense?!

Donielle🎀 • Campbell baby due August 2017
I was reading that babies/toddlers can sense a pregnancy is that crazy or what? Also read that boy toddlers are shows more interest/clingy when you are carrying a girl and if you are carrying a boy shows little to no interest vice versa with a toddler girl. Can anyone say they have had experience with this and can believe it. I have definitely noticed a change in my sons (13 months) behavior since we found out I was pregnant. Very clingy too me and tantrums out the ying yang. Weird!