Ian — guess what, those cells, with very little modification, could be the beginning of a goldfish. Life is like that. It takes months for the genetic code to make an embryo distinctive.
Having a genetic code inside doesn’t make something human. I can cut off a piece of my skin and it has that code. What makes someone human is when they develop into a human.
When we die, our cells remain, the DNA will be there for tens of thousands of years. Doesn’t make us a future human.
You plant a seed in the ground. It grows a sprout. Yes, that will grow into a birch or maple. But the sprout is just a sprout. If you don’t want a future maple, you can remove it, but that doesn’t make the sprout a maple. You could put down a chemical to prevent the seed from germinating, too.
Life develops, it doesn’t just happen. There is nothing inherently human about an early embryo, except your imagination.