Hi! I'm new to this forum but I thought that I should give it a shot to post a question.

So I got this odd question about the possibility to be a relative from a direct line with a person who lived about 2000 years ago (like jesus or something). By direct line I mean going directly down from parent to child and so on, so no cousins or anything is involved. Now to be a little bit more specific so if for instance that every couple would to have 2 children remaining the population at an even level. So i was thinking 2 to the power of 80 (estimating that it would be 80 generations from the year 0 to now). Hear is were I got just too confused and thought to seek help. I got the number like 1.2 trillion or something. But looking at prb.org there have been roughly 100 billion people who has walked the earth. Yeah, here i just didn't know what to do. Anyone care to help? And yes I do know that the numbers I've taken are not close to the actual reality. And I don't consider location of ones own relatives important. Just like in general what would be the probability of one being related in a direct line to a person born 2000 years ago if every couple have 2 children? Any response would be appreciated Thanks in advance!