if i do kundalini yoga, will i still be able to love my girlfriend and have kids with her?

of course, it will not impact your ability to love or reproduce. it will increase your ability to connect with your girlfriend successfully.

The opposite. You will be able to love more deeply because you will understand yourself better, and will be able to be a more loving father. You will be more fertile, not less.

You may need surgery to connect your testicle tubes back to your body.

Yes, probably even better than before. My Steve practiced Kundalini, and I treated him like a God. It was quite literally enlightening.
The concept in Kundalini is self-control. You can direct that control to having everything work for fertilization, or having it work for no fertilization. You can more effectively do your true will. And your true will includes loving and pleasing your lady . . . all I can say is, Oh My God takes on a whole new meaning!

Yes, if you don’t break your neck and become quadriplegic or dead.

Dude, yoga is yoga, like working out at the Gym.
They are suppose to activate your butth0le chakra and all that stuff. Light the internal fire in your butth0le. it’s got nothing to do with you and having kids or loving your girlfriend.
Just remember not to let anybody stick anything up your butt. If they ask you to do that, then you are in the wrong club.