My wife is scared to death of many things, including the possibility our year-old Calico will fall out of a second story window. Lilly (cat, not wife) seems to be of normal intelligence. Have you ever seen this happen?

Many years ago. Cat landed on a sidewalk and wasn't hurt.

My nephew pushed his mothers cat out of the window twice. The cat would lay on their open window on their 2nd story apartment, The cat landed on his feet the first time and was not hurt. The second time it landed on his head and didn't make it.

they are making more of them everyday.
leave the cat alone, it'll fall or it won't.

It does happen. I am more concerned about them getting out of the 2nd story window,climbing down a tree + getting eaten by the coyotes;I have lost several that way,but I am out in the country.I did have a calico that fell off the balcony a few years back but (fortunately) fell into my Salvia flower bed;no harm done.