Oak trees are the product of acorns. But if I sell you a truckload of timber, but deliver only an acorn, I'm reasonably certain you'd complain that what was delivered is not what was described.
This nonsense is one of the most ignorant arguments I hear regularly from feticide rights people. It's flat out scientifically illiterate.
If you order timber you aren't ordering an oak, or even a tree. You're ordering building material. The leftovers from a dead tree.
If you order an oak, because you want to plant trees, acorns might be just the ticket. No amount of timber will do. Because it's not a tree, much less an oak.
But an acorn is.
But being tbe product of pregnancy does not make pregnancy = a person.
Here's another way your pathetic hypothetical can be illuminating.
"Tree" is a lot like "person", in the sense that it's a subjective concept. A tree is not a grass or a bush or an herb. In that sense, an acorn is a tree because oaks have a single woody stem and oaks are trees. If you're a botanist you know an acorn is a tree. If you're cutting fire wood it isn't.
Similarly, the word "person" is highly subjective. To the ancient Israelites, only adult male Israelites were really persons. Here in the USA, a couple hundred years ago, blacks and indigenous humans weren't persons. It was well after the War of Northern Aggression that killing a Native American was recognized as a crime in my home state, Indiana. They simply weren't persons, according to the ethics and laws of the day.
Similarly, while you may have your own subjective opinion about which human beings qualify as persons, there is no doubt that fetal children are human beings. That's the reality.
No amount of semantics will change that reality. You may dismiss the personhood of some human beings, it's been done for all of human history.
But my subjective opinion is that the more human beings are accorded personhood the better the human situation will be.
Tom