Is it true that babys are born without knee caps? If so, when do they develop?

My cousin is a OB-GYN so I went right to the source (I figure a medical degree should suffice.)

Babies are born with knee caps (the patella) but it is formed from cartilige and is not easily visible on x-rays. Also it is not fully boney until around 3 for girls and 4-5 years for boys.

It does form later in fetal development, maybe that's where people get the 2-3 month time frame.

No its not true, the reason they say that is because the knee caps are made of cartilage when born, between 1-2 years they start hardening up until they form bone

True Female

Babies do have kneecaps; they just aren't ossified (bony) so you can't really feel them, which is why most people think they don't have them.

There is a condition called "Nail Patella Syndrome" that is commonly characterized by the absence or underdevelopment of kneecaps and thumbnails.

They are born with cartilage there, as they grow it hardens into bones. It usually starts hardening when they start standing up and/or walking.

Yep!

They typically don't fully develop 'til around 4yrs old (or is it 5), believe it or not. Weird, isn't it? You'd think they'd need them with all the crawling and such...