【英语时差8,16】分娩之痛

（单词翻译）

I’m glad we’re an intelligent species, but boy, that infant head feels mighty¹ large going through that narrow birth canal. And then, after all that, the baby comes out facing down and backwards², which means you’re helpless to assist it, or even to untangle it from the umbilical cord. According to evolutionary³ anthropologists, babies of the earliest humans had a fifty-fifty chance of coming out facing backwards. This was a result of humans learning to walk on two feet. As the pelvis became optimized⁴ for walking, the birth canal developed twists and turns that meant the baby had to rotate in order to keep its head and shoulders aligned⁵ with the widest part at all times. And then our brains got bigger, which meant more twists and turns.And backwards facing babies stupid？ But you know some of the earliest humans learned to compensate⁶ for the difficulty of giving birth by receiving assistance during childbirth, and that made a huge difference in terms of survival. Some anthropologists certainly think so and conjecture⁷ that human females who gave birth to backwards-facing babies, and females who had assistance because they felt particularly anxious about the birth, ended up doing better than females who didn’t. After all, if problems arise during labor⁸, having another person around can make the difference between life and death.