When does life begin?

The increasingly (again) heated discussion around the use of modern methods of contraception is brought about by the renewed efforts to pass, on one hand, and block, on the other, the passage of the Reproductive Health bill in Congress.  

Those who are against the RH bill contend that artificial contraceptives — as opposed to the church-approved natural family planning method — are abortifacients, meaning they kill life inside the womb. And so, the discussion leads to the question, when does life begin? And then to another question: does life begin with conception, or, fertilization? And still another — will the pill and other modern methods of contraception kill life?

The Catholic view, as I gleaned from T.W. Sadler’s Langman’s Medical embryology, 7th edition, Baltimore: Williams & Wilkins 1995), is that “the development of a human being begins with fertilization, a process by which two highly specialized cells, the spermatozoon from the male and the oocyte from the female, unite to give rise to a new organism, the zygote.”

Interestingly, a gathering of concerned individuals was organized by the Catholics for Reproductive Health to listen, and discuss the topic, “Defending our Faith: Forum on Reproductive Health” at the Bahay Kalinaw, UP Diliman, Quezon City. Supporting the meeting were Benjamin D. de Leon, president of the Forum for Family Planning and Development, and Edelina P. de la Paz, M.D., of the Health Action Information Network (HAIN).

Marita V.T. Reyes, M.D., chair of the Women’s Health Care Foundation, and former chancellor of the University of the Philippines, enlightened the audience with her talk about “Biomedical Ethics and RH.”

“In many discussions in reproductive health, one term that is usually mentioned and undebatable is that of ‘the moment of conception,’ as in ‘life begins at the moment of conception.’ It is cited, for example, that science attests to the ‘fact’ that once the paternal and maternal genes (DNA) come together during fertilization, what is formed is a new individual with a unique set of chromosomes! However, when one puts together information from embryology and obstetrics books there several scientific tidbits that can be gathered.

“Conception is usually equated with fertilization described as the union of sperm and egg. Clinically, however, conception is synonymous with pregnancy and is established by a pregnancy test based on the presence of the human chorionic gonadotrophin in the blood and the urine. This hormone is secreted by the chorionic villi after implantation of the embryo.

“There are several details about the process of fertilization that are interesting to know. For example — the semen produced during ejaculation contains an average of 200 million spermatozoa (yes, millions) but that only one will be successful in being activated to fertilize the egg. The life span of the sperm is 72 hrs (3 days) but its ability to fertilize is good for only 24 hours. And it takes about 4 to 6 hours for the sperm to swim across the uterus to the ampulla to meet with the ovum (if ovulation has taken place). Furthermore, another 7 hours is needed for activation of the sperm to fertilize the egg. Only then will the sperm start boring through the membranes of the egg and this takes an hour to complete. Another 12 hours is needed for the sperm to make its way to the egg DNA. It is about this time that the egg itself matures from a secondary oocyte to a mature ovum. In summary, the sperm has so far travelled and is activated for more than 24 hours to finally reach the DNA of the ovum.

“Actually, the alignment of the paternal and maternal chromosomes to form a new genotype (that many would say is the new unique individual) will require another 22-24 hours in a process called syngamy.

“The fertilized egg would have started to divide as it makes its way to the uterus for implantation. At the 8-cell stage (about 2 to 3 days after fertilization, a rather slow procedure) — each of the component cells is totipotent. That is to say that — it is technically possible to tease out each cell from the bunch and allow it to grow as a separate individual. At this stage then — there can be eight potential individuals.

“The developing fertilized ovum is called a blastocyst at about the 32-cell stage (4 to 5 days after fertilization). Before 10 days — twinning may take place, before 14 days — a hydatidiform mole may develop and it is possible for two fertilized ova (in cases of multiple ovulation) to fuse and form one individual. It would seem then that — the union of the a sperm and egg does not always result into a single unique individual, especially if one considers that a hydatidiform mole is one possible outcome.

“Implantation is completed 14 days (2 weeks) after fertilization. Studies have shown that 45-70 percent of fertilized ova do not successfully implant. It is after implantation that individuation may be said to occur since twinning and fusion no longer take place. Some books refer to the fertilized ovum prior to implantation as a ‘pre-embryo.’ After implantation, it is referred to as ‘an embryo.’ Sometimes, debates are unresolved because of differences in terminologies! It is at implantation that the hormone, human chorionic gonadotrophin mentioned earlier, is secreted and is used as an indicator of pregnancy.

“In summary, the ‘moment of conception’ or fertilization is really a process that begins with the binding of the spermatozoa on the surface membrane of the secondary oocyte; noting that it took the sperm 4 to 6 hours to reach the ovum and another 7 hours to be activated. The time needed to complete fertilization may be reckoned at different points depending on our understanding of development and can range from 22-24 hours (when the maternal and paternal chromosomes lie side by side albeit non-functional in the process called syngamy), 4 to 5 days when intercell connections appear at a 32-cell stage; or 14 days when implantation is complete and individuation is established.”

Now, this leads us to the question: when, if at all, does the pill kill life? Marita’s answer was simple. “The primary functions of the hormonal contraceptives (pills, injectables) are to prevent ovulation (therefore, no egg to fertilize) and to thicken the cervical mucus (make it difficult for the sperm to reach the ovum). Thus the overall effect is to prevent fertilization. However, there is a possibility (theoretical effect) that the contraceptive can make the uterine lining ‘hostile’ to the fertilized ovum and prevent implantation. This is what the bishops are harping on.”

My interpretation is that you do not kill something that does not exist. –Domini M. Torrevillas (The Philippine Star)