Targeting the Zona Pellucida

The zona pellucida is a thick membrane that is an outer ''shell'' around the ovum. Penetration of the zona pellucida by the sperm is essential for fertilization. A specific protein in the zona pellucida called ZP3 has been targeted as the primary immunogenic agent. Numerous studies since the 1970s have shown that ZP3 antibodies interfere with growth of the follicle and maturation of the ovum with contraceptive results. ZP3 is responsible for binding action with the sperm at fertilization. This fact has been exploited by administering ZP3 antibodies that then bind to sperm cells, blocking subsequent fertilization by preventing them from binding to the zona pellucida.

C. Future Options for Men

While birth control options for women are limited, those for men are even more so. Other than withdrawal prior to ejaculation, the only choices available for men are condoms and vasectomy. Given the potential permanence of vasectomy, it is not a viable choice for many. Ignoring the facts that some degree of sexism may be attendant to the history of birth control research and that many men and women simply feel that birth control is primarily a woman's responsibility, there are three major physiological reasons for the inequitable emphasis on female rather than male directed approaches. First, since fertilization and conceptus development occur within women, there are a greater number of reproductive events to manipulate to prevent pregnancy. Second, since women have to centers of ''brain control'' of the endocrine events controlling the activities of their ovaries and men have only a single brain center of testic-ular control, it is easier to hormonally interrupt the events controlling female fertility without causing adverse effects on the production of the hormones needed for other body functions. Third, and perhaps most important, it is difficult to argue with the logic of attempting to prevent pregnancy by controlling the fate of a single ovum produced once a month compared with the overwhelmingly more difficult task of interrupting the continuous process of sperm production which yields 20 to 30 million spermatozoa every day of a man's reproductive life, or of trying to control their fate following ejaculation. And the fact that women generally ''have more to lose'' if an unwanted pregnancy should occur also argues for giving women the greater control.

Pregnancy Nutrition

Pregnancy Nutrition

Are You Expecting? Find Out Everything You Need to Know About Pregnancy and Nutrition Without Having to Buy a Dictionary. This book is among the first books to be written with the expertise of a medical expert and from the viewpoint of the average, everyday, ordinary,

Get My Free Ebook


Post a comment