From the Kansas City KS Star. 5/22/1926:

DEATHS IN GREATER KANSAS CITY.
HEINLEIN—Rose Elizabeth Heinlein, 7 years old, died today at St, Luke’s hospital. She is survived by her parents, Mr. and Mrs. R. I. Heinlein, 2102 East Thirty-sixth street; four brothers, Lawrence L. Heinlein, 4901 Highland avenue: Ivar Heinlein and Robert Heinlein, United States Naval academy, Annapolis, Md., and Claire Heinlein of the home, and two sisters, Louise Heinlein and Mary Jean Hemiein of the home.

This is the daughter that fell out of the car Rex was driving, right?

The sort of thing that's a world-changing tragedy for any family in any era.

I don't think I'd heard of the falling-out-of-the-car story. Is that in Bill's biography? If so, I missed it.

My mom was born in 1921, and when she was a toddler, she was riding in the back seat of the family's open-top car while they were driving on a bumpy dirt road. In the front seats were her parents, with her father driving; sharing the back seat was her older sister, Betty. They hit a bump and my mom bounced out, rolling down into the ditch by the side of the road, unharmed. The funny family story is that Betty thought to herself for a moment, "Should I tell our parents?" She was apparently contemplating the advantages of being an only child again. Eventually she said in a quiet voice, "Margaret fell out." Their mom turned around and said, "What?!?" Betty replied, "Margaret fell out," and their mom screamed and exhorted their father to go back and get her.

All's well that ended well in this case, but if Heinlein lost a sister in a tragic version of the same kind of accident that, for my family, had no serious consequences, then I feel an even stronger connection with him.

I think Bill has some details in the biography, but as I recall she fell out of the door and was run over.

But yeah, having even a benign incident of the kind in your family history makes it sting a little more. A couple of times we've "lost" kids for five or ten minutes, and that gives me just a peek over the fence at what parents of abducted children must feel.

The same thing happened in my wife's family. My mother-in-law ran over
one of her daughters. She was backing out and didn't see her. Debbie did end up in the hospital with broken bones, but survived with no problems.

As a bonus she met "Dr Kildare" ie Richard Chamberline. It happened when his
show was popular and he visited the hospital.