Is it really possible for the doctors to check if you are virgin in real life?
To a point, yes. Assuming you are genetically female anyway.
In RL a doctor (or anyone else) can look to see if a female's hymen is intact. If it is, then she is a virgin, though this has problems to be a definitive determination.
The problems are that the hymen can be torn though non-sexual activities. Also, there are things that can be done that most people would consider sex, that would not tear the hymen.
Basically, the best a doctor can do is look at a girl's hymen and say if it has been torn or not.
One last problem, though I would suspect that a doctor may notice this, is that a hymen can be resewn... at least if what I've read about Madonna is true.