Assuming the average length of time between familial generations is approximately 25 years, how many people had to have had sex since the year 1 A.D. in order for you to be here to read this question?

As asked.

From what I found the average amount of time between generations in developed countries is in the high 20’s to low 30’sand in less developed countries it is in the high teens to low 20’s which is why I assumed 25 years figuring that no matter how developed they were in 1 A.D. they would be considered third-world by todays standards.

And assuming no parent went on to have sex with their offspring.