According to Whelan (author of A Baby. . . Maybe, 1975), everything Rorvik and Shettles told you about choosing your baby's sex ain't so. We suspicioned that. But we're not any more sure about this than we were about the other. And neither, apparently, is the author, who allows that she can only offer us a 36 percent greater chance at the choice of having a boy, and a 16 percent greater chance of having a girl by identifying ""boy days"" and ""girl days"" on the basis of analyses of vaginal secretion, basal body temperature, and insemination timing. In early cycle inseminations, 68 percent of the babies born are male, she says. When intercourse takes place on the day of ovulation, the percentage of girls increases to 56 or 57 percent. Whelan mentions that Egyptians would dig two holes in the ground, put barley in one, wheat in the other, and instruct a woman to urinate on the holes. If the wheat germinated first, the prediction was for a boy baby. Barley presaged a girl. Sounds as scientific as this.