I think it's more the fact that the Russians likely wouldn't be selling their "good" nukes. They would be selling the old, run-down ones. They would be a large chance they wouldn't detonate properly.
There's also a lot of debate on how well the rest of Russia's nuclear arsenal has been maintained. It's highly specialist work that can't easily be verified by non-specialists. I wouldn't be surprised if a lot of Russian nukes were already non-viable due to corruption affecting maintenance.
The problem is that, in this situation, no decision IS a decision.
Up until puberty, boys and girls are quite similar. It's puberty that causes the lifelong changes. We already know that delaying puberty doesn't cause long-term issues. Puberty blockers are used to treat or help with other conditions. By blocking puberty, you are buying time. Time for the child to mature. Time for phycologists to assess. Time to practice the role before locking it in permanently. Time to grow, learn, and make the very decision you are talking about.