explain that again ...

"Without the adaptation of a more curvy lower spine, pregnancy would have placed a heavier burden on back muscles, causing considerable pain and fatigue and possibly limiting foraging capacity and the ability to escape from predators.
"Any mother can attest to the awkwardness of standing and walking while balancing pregnancy weight in front of the body.
"Yet our research shows their spines have evolved to make pregnancy safer and less painful than it might have been if these adaptations had not occurred."
There is a gene that makes a person into a “Scientist” and a very important genetic mutation that occurred as part of that gene gives them an extra ordinary imagination in order to accurately “explain” not only How evolution works but also Why.

Here we go again. IF it IS evolution there can NOT be a reason Why ! !