I was close to having a so called frustrated plan.
Started out a game as Lombardia, TASS mod.
It was going well, two sons both fairly decent. Welll....
The oldest as soon as he was 16 decided to be gay, losing 7 fertility on the spot and the modifier gives -7 fertility to say the least. At this point, I was like, okay... might as well marry a decent stat lady and make money, I still have my youngest son.
So, on to the youngest, after marrying him to a decent intrigue woman... gets her impregnated and he gets the balls to get me to abdicate my throne.
At this point, I tell him to kill himself. I like my current ruler and I didn't like my uppity son. My wife died as well...
Soooooo... at this point. I was in anger. No heir.
Married a new fertile teenager wife, leader pushing 56. The spy master heired a grandson. My main leader heired a son.
I was quite impressed at my situation.
Although the daughter in law took away my only grandson to German lands where I never saw him again.
So close to having no dynasty as the homosexual son of the first never sired a child.
Granted his young brother claimed the throne of Italy, and due to assasination of a his (King of Sicily) inheriting son... gained claims to Sicily.
Effectively uniting Italy, although there are some strays.
He died fighting muslims in Tunisia, which was eventually gained.
Italy is obscenely wealthy...