I didn't say anything about 6 weeks or any specific time frame for the heartbeat to exist.
The question is whether or not the thing in the woman is "alive" before it's viable. For some, life begins at conception. I don't agree. The dividing and multiplying of cells is really no different than cancer. There's nothing you can point to and say "that thing is alive". I think a heartbeat is a sign of life and that's true throughout the medical world. A doctor or surgeon uses a heartbeat to determine if John Doe or Jane Doe is alive, right?