What if 'Y' means the male head of the ruling family? Here is an interesting website chronicling lineage of the british royal family. Many are 'bastards' if real anaylsis were done according to this overview.

http://www.sarkasfountainpen.com/p/blog-page_6.html

Considering hidden technology what if fertilized eggs of 'Y' selected heads family are inseminated into selected women (to carry out pregnancy) in this current world to carry on specific 'bloodlines'?

http://www.sciencemag.org/site/feature/data/genomes/258-5079-60.pdf

What if cloned models of heads of families are grown and coordinated deaths are set up (timed) to transfer souls to the new body; which does have a similar growing age as real humans. or that I can only assume they do , right now.