Hi bee
It is impossible to guarantee a pregnancy of twin boys. If you have a genetic disease that is only passed onto girls, then you can have embryo implantation, and the doctor can only select a male embryo. It may be possible that the doctor will implant 2 eggs, this is very unlikely and would probably only happen if you were unlikely to be able to be pregnant more than once.
If any of this information is relevant, you should speak to a fertility doctor to understand your options.
best of luck to you.
