But that's not quite true either.
In law, the interests of the blob change as it grows and becomes a foetus.
And the host woman's duties change with it.
How you frame the progression of those interests and duties is reasonably a matter of discussion and law.
But for the majority of people, the heartbeat isn't a particularly relevant moment. It's a mechanism. The thing that matters is when the blob becomes sentient, after which it wants protections.
Fortunately, the vast majority of mothers provide it and don't need the law to tell them to be protective. That's the status quo ante Texas.
If only it wasn't the ghastly Republicans on the other side of the argument, it could be a helpful conversation about rights and duties and how they change. But they'd rather create a surveillance state than listen.
Hard to see how the states remain united in the face of these republicans.