From what I read about it, it sounds like basically, yes, scientists put together what they deemed a representative sample and analyzed their discharge on an ongoing basis. I’m only assuming they knew what they were doing.
Here is a USCF Medical Center page making the 50 percent claim, although it doesn’t go into how that number was arrived at:
In nature, 50 percent of all fertilized eggs are lost before a woman’s missed menses. In the in vitro fertilization (IVF) process as well, an embryo may begin to develop but not make it to the blastocyst stage — the first stage where those cells destined to become the fetus separate from those that will become the placenta. The blastocyst may implant but not grow, or the blastocyst may grow but stop developing before the two week time at which a pregnancy can be detected. The receptivity of the uterus and the health of the embryo are important for the implantation process.
This really has no bearing on what Catholics ought to do regarding conception and pregnancy, since contraception is immoral at any stage whether a baby has been conceived or not.
I’ve found some pages arguing that we shouldn’t be opposed to various actions that lead to the destruction of embryos because most of those embryos would have died naturally anyway. That argument is pretty lame – everyone will die at some point; that doesn’t give us the right to take innocent lives with our own hands.
I saw an article headlined “Is Heaven Populated Chiefly by the Souls of Embryos?,” which I thought was kind of an interesting theological question, but not really what the article was about. The headline was just a flippant introduction to the kind of argument I mention above.
Another article argues that, if we really consider all fertilized eggs to be human beings, we ought to be in favor of legalized, widespread use of birth-control pills that, statistically speaking, would (according to the article) reduce the number of zygotes that would be created in the first place and therefore die.
This argument is interesting, and I have to admit it took me a while to recognize a few major problems with the author’s reasoning:
- She ignores the moral distinction between natural death and the deliberate taking of innocent human life.
To be fair, the author is unconvinced that birth-control pills actually acts as abortifacients. She accepts the premise only for the sake of argument. Still, her rebuttal is that if the number of deaths resulting from taking of a pill (a deliberate act) is less than those that would have died naturally, than taking the pill is to be commended.
- She assumes that it is better for a human being not to exist than to be created and die in the womb.
We don’t know what God’s plan is for unborn children who die naturally in the womb. For all we know, in His divine justice and mercy, He brings those children straight to Heaven, where they are made perfect by Christ and offer prayers for those on earth and in purgatory, with prayers that are especially pure because these children never knew sin. Or, maybe God has another plan, but we know that God is good and so are His plans.
If one reasons that it is better never to exist than to die early, the question I would have to ask would be, how early? How much earthly life must one be given before their existence will have been a good thing? Human life, regardless of how long it persists, is sacred.
- She assumes that contraception itself is a morally acceptable means of preventing pregnancy even if it caused no lives to be lost.
She is of course not alone in or culture in making this assumption. Too many in our society lack proper respect for the marital act. Even many of those who oppose abortion see no problem with contraception, so long as that contraception cannot act as an abortifacient.