Henry Olsen has a commendable article about a commendable law: Iowa’s new effort to educate students about the early development of human beings. But two words in the article, in my view, slightly marred it. You might say, then, that I have a microscopic objection to his description of microscopic human beings.

The two words are “fertilized egg.” That phrase is often used, but it is misleading. It makes it sound as though the new entity that exists after fertilization remains a gamete — an egg — albeit a modified one. But the embryo (whether we are talking about an embryonic human being or an embryo of any other species) is not a gamete. It is not an egg.

Upon fertilization, the egg (also called an oocyte) and the sperm cell that fertilized it cease to exist, their union having given rise to a new embryo. That embryo contains genetic material from the oocyte and sperm cell, but unlike the gametes the embryo is both genetically and functionally distinct. It is a whole self-integrating organism, not a part of another organism (as the gametes are parts of the male and female progenitors of the embryo).

So, the human being that is now an adult (such as the one reading these words) is the same human being who at an earlier stage in his or her development was an adolescent, and before that a child, a toddler, an infant, a fetus, and, at the very beginning, an embryo. Those words do not denote different things, or different kinds of things; rather, they refer to the same thing — in this case a human being — at different stages of development. By a gradual and internally directed process, the human being that is, let’s say, you the reader developed from the earliest embryonic stage (what embryologists call the zygote) into and through the fetal, infant, child, and adolescent stages and into adulthood with your unity, determinateness, and identity intact. At each stage what you needed — all you needed — to survive and develop was nutrition, a hospitable environment, and freedom from disease, accident, or violence.

And, for current purposes, here is the crucial thing: You (or me or anyone else) was never an oocyte or a spermatozoon — those were parts of your parents. You (and everyone else) were, however, once an embryo, just as you were once a fetus, an infant, a toddler, and an adolescent.

Henry Olsen did not use the misleading term “fertilized egg” to dehumanize embryonic human beings, or to distract readers from the scientifically verifiable and indeed undeniable fact that they are indeed human beings. There are, however, people who use the term precisely for those purposes.  I would urge everyone who cares about truth and clarity to avoid using it.