Daryen! Good to hear from yu!
So identical tins is the genetic crapshoot and Fraternal's are inheritable. Coolness! Congrats on your set!
Back on topic--
barring an OTU typo..
The theory that works best for each GM's TU in this historical legacy of the line of Emperor's/ Empresses of the 3rd Imperium could take either the inheritable gene path,
or the two birds in basket exvitro as his excellency Marquis Cooper points out. After all, high-tech geneering such things as gender predisposition is a snap (as my Dr/Academic /Professional players tell me).
Just to stir things up a bit..
WHAT if:
The individuals Margaret & Paulo I are one and the same?
What if the Imperial heir changed her gender and the Imperial Historians rather than scandalously reporting same, merely "added" the male personae as her brother?
I could see someone researching Imperial line history suddenly running into a lot of closed files and stonewalls. [For those of you with campaign adventures of a non-violent nature mostly].
Not to mention, possibly drawing all sorts of the wrong attention from the highest levels of the Imperial government..
:devil:
--the premise of this is a relatively easy one: Historical revisionism. Look at the USSR after Stalin--they rewrote the era for schoolbooks in the Khruschev era. Then again, in the Brezhnev era. It maybe that in justifying who was legit in the early rebellion [1116-1120] some "revision" might have occurred.
Personally, whichever works smoothest for you is the right way to go.
have a great day!
Slainte!