Estimated Extinction Probabilities:

Studies and simulations suggest:

With 1 child per generation, and assuming a 50–60% chance each descendant has at least one child, the chance of extinction by the 4th generation is over 80–90%.

Even with 2 children per generation, there’s still a 20–40% chance of extinction within 4 generations, unless fertility remains high and consistent.

🧬 DNA Transmission Note:

Even if your line doesn’t go fully extinct, your DNA gets diluted by ~50% every generation:

Your child: 50% of your DNA

Grandchild: 25%

Great-grandchild: 12.5%

Great-great-grandchild: 6.25%

By the 4th generation, it’s possible for some of your autosomal DNA to be completely absent in a descendant due to recombination randomness, unless you had multiple children who each had children.

(http://www.autoadmit.com/thread.php?thread_id=5738724&forum_id=2#49021610)