I have a friend that's really into child safety and emails everyone articles. Today I got this one: Rear face in car seat until 4? Seems really excessive to me, no? And the photos look uncomfortable, contrary to "contrary to belief, this is comfortable".

Here's the link, but if you can't open it I'll include text.
https://www.facebook.com/lauravdn/media_set?set=a.10151606771554043.1073741830.688419042&type=1

"Rear facing a child in a car is recommended to age four because this is when the cervical vertebrae are close to being ossified into one piece of solid bone rather than three bony pieces loosely attached by cartilage. Before ossification happens, the head of a forward facing child can stretch the spinal column quite far in a crash. If the spinal column stretches too far, the cord stretches. If the cord stretches, it can suffer permanent damage or even be severed, leading to life long impairment or death. US studies have found a 534% increased risk of death or serious injury for forward facing children. This is why NHTSA, the federal agency regulating traffic safety on our nation's roads, promotes rear facing to four, which technicians and advocates echo." - J.S. certified Child Passenger Safety Technician-

EDITED after OP: As seen in my reply below, this is a reaction by someone that AS OF YET knows nothing re car gear (because she's pregnant and hasn't bought anything/researched YET). I always thought 2 was the norm, so seeing this was definitely a surprise to me, as I am sure it will be for many others, and I'm glad we can post articles on HB to ask for thoughts.
Thanks