How can I get my son's sexuality tested?

To get my mind off today (that entry will come later), I was reading Daniel Tosh's blog, which is mainly a continuation of viral videos he already talked about on Tosh.0, when I came across this:

How can I get my son's sexuality tested?
Gary honestly asked the following question:
I am worried my son might be gay. I want to get him checked. Isn't is possible to get a hormone check? A vocal cord check? Can't a doctor indicate if he is gay or not? My son has almost no muscles and narrow shoulders. He also has blue eyes. He talks in a very high voice and while he sings he sounds like a castrato. He tells me his voice is called tenor. How can I test if my son is gay?

I'll give you a minute to digest the question and/or stop laughing before you continue reading.

How to test if your son is gay:
What type of music does your son enjoy listening to? Does he spend his time listening to Metallica or Lady Gaga? Does he know all of the words to Guys and Dolls? If he can recite any musical by heart, chances are your son is gay.

During a father/son bonding session, try to discuss a movie with your child. During the conversation, be sure to bring up a movie with (insert current hot actress name here) in it. Does your son respond by discussing a feature of the actress or her acting skills? If he's more interested in her acting skills, chances are your son is gay.

Does your son prefer Playboy or Playgirl? If he has a secret stash of Playgirl, chance are your son is gay.

There is nothing wrong with children joining the choir/band/orchestra, but "straight men" don't dance. Has your son expressed interest in joining a dance studio? Does he want to learn ballet or tap dancing? Has he ever wanted to go to a club to dance, rather than flirting with women? If he prefers choreography to bumping and grinding, then chances are your son is gay.

All men born with blue eyes are gay. If he has blue eyes, then chances are your son is gay.

Finally, you could always check is anus. Is it torn and red? Does he enjoy getting enemas a little too much? If he enjoys enemas and has trouble sitting down in wooden chairs, chances are your son is gay.