hi! similar questions come up in this sub quite often, i.e. "Is Genghis Khan/Charlemagne/William the Conqueror/whomever really the ancestor of x% of all Asians/Europeans/British/whomever?", and the TL;DR is yes: broadly speaking, everyone - including goat-herders - who lived several hundred years ago and produced at least grandchildren is the ancestor of a great many people living today.

Here's the most recent post on this:

• How realistic is the Genghis Khan genetics theory?

and see this one, which has a longer explanation of the math involved, plus links to several other posts, including an excellent AMA in /r/AskScience with a pair of geneticists

• A question about European History and common ancestry.

A couple of caveats when reading these threads, since comments are not always clear about what they are referring to:

• "Descendants" are Genghis Khan's children's children's children's ... children. As a hypothetical example, imagine that after 2 generations he has 4 children (2 sons and 2 daughters), each of whom have 4 children (2 sons and 2 daughters): that's 4 + (4*4) = 20 descendants.

• "Male-line descendants" are Genghis Khan's sons' sons' sons' ... sons only. Using the above example, after 2 generations he has 2 + (2*2) = 6 male-line descendants (that is, his two sons and their sons; his daughters, his sons' daughters, and his daughters' children are excluded). This is the group that Y-chromosome DNA evidence refers to (see next point).

• Y-chromosome DNA evidence does not prove descent from him personally, but from people with genetic markers which he (may have?) shared