The Generic Villain continues a point-by-point facedown and update of that reference material of all baddies with imperial ambitions, The Evil Overlord List.
So. Eighteen and nineteen, which basically boil down to “never have kids, ever” and… well.
My first problem with these things is that they’re pretty obnoxiously sexist. The son’s ineffectual and guaranteed to rebel (ineffectually), the daughter’s pretty but thinks with things that aren’t her brain, if all the good girls like bad boys all the bad girls are likely to want good boys… yeah, that. “All X do Y”, when applied to human behavior, particularly when it has to do with your subordinates, your opponents, or anyone who may end up as both, gets you killed. Usually in an ironic way that doubles as a way of disproving whatever generalization you happen to have lived by. The Laws of Dramatics love that sort of thing.
Second is that it seems to immediately go to “and there goes the neighborhood”. What are you doing that guarantees your son’s going to rebel, and why isn’t he properly trained? (Come to think of it, is he rebelling against you because he isn’t properly trained? If I found I was apprenticed to someone who was deliberately keeping me from learning anything particularly useful due to some fear that I would rise up and overthrow him… well, let’s just say the last time someone tried to pull something like that on me was how I ended up with my first citadel and discovered the joys of heads on pikes. I’m pretty sure my response isn’t an unusual one. But I digress.) Why is your daughter so completely isolated from decent romantic partners that The Hero can just sweep her off her feet by blazing in and Doing Hero Things?
Third is that it makes it sound like the kids are completely separate entities from you—not just in the “Well, duh” physical sense, but organizationally as well. I’ve written about dealing with your children. Most of it can be summed up as ‘know how you want them to grow and don’t ever, ever underestimate them’. Let me add now, “Work with them.” You don’t need to make equal partners of them, but a little bit of give and take doesn’t hurt; find things that they can help you achieve, find goals of theirs that you can help them achieve, and so on. If you’re not treating your kid like a dog, the kid’s far less likely to go for that old canine standby of biting the hand that feeds them. (Besides, rebellious progeny who think they know everything do make pretty good advisers, just from the fact that they’re trying to show you up. If you want to make sure you’ve got a plan that’s thought of everything? Encourage the kid to try to take you down a notch or come up with a better way of doing what you’re doing. You’ll both profit.)
(And seriously. Those of you with the daughters who are betraying you because they’ve fallen in love with the protagonists? I’m willing to bet half the problem there is that they don’t know the difference between love and lust and haven’t figured out that they’d be better off just clunking the hero over the head, brainwashing him and killing him when they tire of him. So many problems would be solved that way.)