The Biology of . . . Morning Sickness

"If you ever cook meat in this house again, I'm leaving." Those were not the words of a vegetarian but of a woman eight weeks pregnant with a whiff of steak up her nose--my nose. Usually, I was happy to chow down on a hunk of meat, and I hadn't lost my appetite for most other foods. But suddenly, the smell of broiling cow had me heading for the toilet. Of all the things I could have hated, why meats?