January is one of the times during the year that our attention turns to abortion. Some prominent advocates for abortion have changed their mind when they saw an ultrasound. They could no longer deny the biological humanity of the fetus with his rapidly fluttering heartbeat, tethered like an astronaut by the umbilical cord, and floating in amniotic space.

But what about the tiny human beings who do not catch our attention through ultrasound? Of course, I’m talking about embryos created for IVF or for research. Politicians sidestep the issue by saying that these human beings are different from those in the womb. Researchers scold us for imposing our religious views about the soul of the embryo.

Whether or not an embryo has a soul is a fundamental theological question. But science itself can answer the question about the humanity of the embryo.

Biology evaluates an organism in terms of its structure and dynamic. Is it an organized entity, or just a random collection of cells? Does it grow and develop over time? An organism is a unified, self-directing entity that endures and develops over time, even as the individual cells are replaced by new ones.

Is a human embryo an organism?

Well, once the human egg is fertilized, the new zygote takes over her own development with fascinating efficiency. Unlike the egg or sperm, which die within hours, this new organism is designed to live for decades. She is distinct from her mother and father. Her DNA is what we’d expect for a human being, and her genetic identity does not change. A human embryo is not a Transformer, and she won’t become a flower or a frog, or even a different child.

She is a very tiny member of the human species, looking just like a human being should look at this early age. Given time, nutrition, and a welcoming environment—like a womb—she will grow into a fetus, then an infant, toddler, and so on.

When we say that an embryo isn’t human because he’s so tiny, “no bigger than a dot,” that’s discrimination based on size. If we say he’s just a ball of cells in a petri dish, that’s discrimination based on appearance. If we say that these embryos are leftover and will be thrown away, so why shouldn’t some good come out of it, that’s discrimination based on unwantedness.

We have discriminated against other human beings in the past for similar reasons. It’s time to stop. The human family should be welcoming, not self-serving.

This is not a critique of IVF itself, but of what can come after. The burden of proof is on those who want to exploit embryos for research, for science itself points to the embryo’s humanity. We would not subject a toddler to harmful or lethal experiments. Embryos deserve the same care.

We don’t need ultrasound to make that case, just good science and moral reasoning.