Chinese Sperm Bank

Apparently this is how dudes donate sperm in China. I wonder why China even has sperm banks. I thought they were way over-populated there. Maybe they are exporting the sperm.
I bet the job ad for this place reads something like this:

"An internship here really offers hands-on experience. It’s a growing field with small rises and falls of course. Collapse is always a possibility. Our staff is always hard at work. (Tip: You don’t want the stock option though unless you have the freezer space.) Potential employees who want to make a splash in this industry are welcome to apply. A firm grasp of biology is recommended. Why not start your career with a happy ending?"

Why are the guys wearing masks, but the “nurses” aren’t?