That is what happens when you help your son with history and don't pay attention to spell check... But I will say, Genealogy can be all you have to find a lost tower/keep/cave...
A Human Generation is 30 years because we normal have kids by that point. As metallion states there is no reason for an elf to think that way. They can have kids till someone sticks them with a sword or they grow weary. So there is no reasonable way to track it.
It is one of the suggested character backgrounds in the Xa-Ar module that your character be descended from the union of a lost Mah-Ilari prince and a noblewoman from Urulan. (This event happened early in the second era and is given a firm date in the timeline. 1540, IIRC.)
If he is willing to warm the sheets with this women then why isn't he willing to do it with another?
At the same time, use that awe to your advantage. Finding a name or possible link to a family member or lost Prince should be like trying to find the one specially marked golden needle that is somewhere on earth.
BUT you are gaming. Make a prince, give him some things that are hard to question that only work for him or his siblings but not his mother or father. It has to work for one of them to make sense.
Make it clear that researching his lineage is near impossible. Time is hard to express to people, perhaps they have to just go with it.
I've just been trying to imagine how hard it would be to keep eleven millenia of family history straight. My real-life family has been in America since 1597, and I can't even keep all of that straight
In our World, there is almost always a paper trail. Sure there are huge tracks of history that are hard to track. Most nations keep some sort of paper trail when people are involved. Just look at the Domesday book. It is simply the most famous of all the inventories done.
In Europe, Royal families tracked each others lineage as closely as their own, so if something went wrong they had other resourced to compare to... if that particular court was willing to share of course.
1539?1541: Sirdia-Mah?s elder son Kelis travels to Urulan. [There he has an affair with the Loar-Elf Lady Celtira Mentaka and she becomes pregnant, but does not tell him. Kelis leaves before the pregnancy is obvious and is killed on the return journey, never having learned of Celtira?s condition; she later bears a son. The boy, his descendants, and Valaan are the only remaining heirs of the Mah-ilari royal family.]
Some of the descendants leave Urulan and end up in Remiraith, the lands that become known as Tanara or even Emer. I would bet there are still blood lines in Urulan. So at that point, your family line would be traced through Urulan, which suffered a civilization setback. I would guess they shared information with Remiraith which has a large Family tree filled with question marks. In truth you only have to go back 4 breeding sets of parents. Presume 2 sets of children each and you are pretty safe. Truth of heritage would be some of the lost items.
LUNCH!