National Geographic : 2006 Nov
education, labor support, and maternity nursing. Let me set the record straight. Birth is not the same as shoving a hard model skull through a hard model pelvis. The fetal skull and maternal pelvis are both flexible living tissues. Second, the shape of the pelvis is not a "marginal" design. It is a labor-saving device, based on the inclined plane principle. Next, a fetus does not have "broad, rigid shoulders." The unborn infant's shoulder girdle is flexible and compresses into a cylindrical shape during passage through the pelvis. DENISE P.GROSE Columbia City, Indiana When women give birth in an upright position, instead of lying in a semi-reclined position, which pushes the tailbone closer to the pubic bone, the pelvic opening is normally ample. When unaffected by pain med ication, the baby is normally adept at making the rotation in the birth canal without assis tance. Although human birth may be more complicated than primate birth, it is not nearly as dangerous as the article implies. Unnecessary inter vention in the natural birthing process, however, is. DAWN WOODRING Lake Ariel, Pennsylvania I was distressed to see a show biz chimp used for a photo shoot. These animals are usually pulled from their mothers and are never socialized as chim panzees. When they become too large, strong, and unpredictable to be used by the entertainment industry, they are outcasts, and these social creatures almost always spend the remainder of their long lives in isolation. KIMBERLEE RAYMOND Chicago, Illinois Photographer Cary Wolinsky replies: Everyone involved in this project, NATIONAL GEOGRAPHIC staff and researchers at Harvard University and University of Write, Email, Fax Write National Geographic Magazine PO Box 98199 Washington, DC 20090-8199 Email firstname.lastname@example.org Fax 202-828-5460 Include name, address, and daytime telephone. Letters may be edited for clarity and length. It is what makes air bags, flexible bumpers and saving lives possible. It is chemistry.