That might be it all right. I only really had 3 male family members and due to a massive war with the HRE, Denmark and France I managed to take huge swathes of land. Since the 3 men of my family were all around the same age they all had children (male children) at around the same age. So now I've reached a point in the game where all their children are coming of age and the adoption candidates have ceased their petitioning. Thanks anyway folks :)