at conception

conception and ensoulment

You have your own unique DNA at conception

Depends on your definition of life. You could say the first heartbeat signals life, but there are plenty of living things that don’t have a heart so that doesn’t really work.

You could say it’s the moment the egg is fertilized and the cells begin to split exponentially, that is probably closest to the scientific definition.

Ejaculation. Those sperm cells are definitely alive.