I am going to poke holes in my brother's condoms.
Why would you do such a thing? In some countries, it's considered as a crime.
I'm sure he likes younger women, so he needs to pay the price.
As long as the women are of age, then it's none of your business on what he does with them. You should be ashamed for messing around with his private things, and potentially getting someone pregnant. A new life is such a big change in someone's life, and you can't cause that when they're not ready.
He is still a man, part of the human reproductive cycle, in fact the part that he performs is much more complete than what I do. So, I'm going to shove his responsibility back in to his lap.
You don't get to decide that stuff. If he gets some pregnant through his own fault, then he'll have to deal with it, but you doing on purpose is evil.