EDIT: I'm disabling the comments for this, because I've finally realized, after all this time, that none of the detractors will ever come up with something that I haven't already debunked.
I know, I know, if you're new to this, and happen to disagree, it sucks that you won't be able to voice it. But trust me, you wouldn't bring anything new to the table.
I've heard all you've got to say already. Really, I have. Just trust me on this.

This way, both of us will be able to avoid wasting our time on this issue. Since you wouldn't have anything fresh to say, you'd simply feel frustrated because I wouldn't be putting any effort in replying to you, even though you feel (mistakenly) that you deserve better. It's not worth it for you, nor is it for me.

Imagine a scientist constantly being "challenged" by flat-Earthists, and you will see the situation that I find myself in.

If you agree, fav it, and if you suck at science and therefore disagree, don't. But there really isn't anything left to say on this issue, so I'm closing this case for good.

During the last few days, I have been secretly conducting a very serious scientific study about the a group of people holding an extremely disturbing set of beliefs. To accompany this stamp, I will present you with the data that I have collected through my interaction with 3 of those dogmatic believers:

Male Sheik Supporters: The sad story of those who refuse to accept reality

First of all, it is important to note that out of the many male Sheik supporters (henceforth Malesheikists) that I have encountered, not all of them are as dogmatic and confused as the people that I will be describing below. If you are one yourself, please do not feel like this article is targeting you specifically. To protect confidentiality, no username will be given out in this article. I am now presenting your with a few characteristics present in all 3 of my test subjects:

1.Dogmatic worldview, characterized by a refusal to accept evidence going against their pre-conceived notions;

2.High level of mental instability; subjects hold confused ideas, such as the belief that a person can, in real life, actually transform their gender simply by claiming to be of the opposite gender (yes, such people exist);

3.A deep misunderstanding of human anatomy and of the differences between male and female human beings (more on this later);

4.Chronic liars using erroneous facts and logic to support their twisted world view; inability to understand simple and correct analogies, as well as elementary mathematics, a shameless tendency to twist their opponent's arguments to make them appear contradictory;

5. When losing a discussion, subjects brought friends who agree with them in order to spout the same old, tired, non-sequiturial arguments, as if the number of people repeating an absurdity will somehow have an effect on the absurdity of what is being said;

6. The desire for Sheik to be male so that perverted art depicting her with male genitalia can be produced and fantasized to (will of course be denied vehemently, but a quick look at a Malesheikist's page is proof that this is nothing but the truth).

Now, as everybody who is familiar with the Legend of Zelda series (aka non-noobs) will tell you, Sheik was in fact the false identity that princess assumed to conceal her true self from Ganon during seven years. Sheik is in fact, nothing more than the name we call Zelda when she is lying about her identity. In other words, Sheik is a falsehood, a lie. It therefore follows that if Zelda is female, (which she is), Sheik is female also. In other words, discussing Zelda's gender is the same as discussing Sheik's gender. This can be described mathematically by saying that if A=B and B=C, then A=C.

As if this simple and irrefutable proof wasn't sufficient, to add credibility to this fact, we have other videogames containing canonical information (such as the trophies in the Smash Brothers series) explicitely describing Sheik as female, as well as several statements from Nintendo employees (it should be noted that although trophy information is accurate, the storyline of the Smash Brothers series is not).

Malesheikists would have you believe that there is some kind of controversy or debate to be had about this issue. In actuality, Sheik's gender is known with as much certainty as the shape of planet Earth (as demonstrated by the above facts). They will of course brush these facts aside, since acknowledging them would mean having to reject their mistaken beliefs. It has been claimed, without supporting evidence of course, that Zelda used magic to transform into a male. However, when pressed for evidence, Malesheikists will go on an illogical jabber consisting entirely of false informations, twisted facts, and analogies that do not follow logically. There is, in fact, no canonical information to support this claim outside of fan fiction, which is exactly what one would expect since Nintendo has confirmed that Sheik is female.

To save face, the Malesheikist will attempt (but fail) to philosophize, to muddy the waters, and to claim that gender isn't decided solely by what is found between a person's 2 legs. It is of course unncessary to go into deep detail as to why this claim does not have a leg to stand on. As most people over 5 years old will tell you, the difference between male and female is that males have a wee-wee and that females do not. It really is that easy and simple. However, during this study, one of the test subjects has made the statement that "declaring yourself a male (if you are female) actually MAKES you a male". It should be obvious at this point that the state of dementia in which these people live their life goes far beyond what one can find in your average internet user. Again, since Sheik is Zelda and since there is no evidence that she grows a penis when undergoing the transformation, the burden of proof rests on the shoulders of the Malesheikist, who, without mistake, will fail to produce any kind of evidence whatsoever. It is nothing but an unsupported assumption which has been discredited by Nintendo's statements.

They may also try to compare it to cosplaying as a male character, which doesn't make the character female. The obvious omission is of course that cosplaying as another character is different from assuming an identity that you have created from scratch to conceal your own identity. Do not forget that even if a Malesheikist argument may sound credible at first glance, there is always something wrong with it if it can be used to support an incorrect idea.

To conclude, I will reiterate that although all Malesheikists are holding on to an absurd and mega-discredited idea, the observed test subjects described in the above study do not represent the state of the majority of them. If you ever encounter such an individual, the correct thing to do is to repeatedly ask for arguments supporting their ideas. Malesheikists will of course repeat the same already refuted arguments even after you have pointed out the obvious falacies that they contain. Do not go on the defensive; remember, you are not arguing, you are simply stating an objecive fact of reality (Sheik being female). Do not bother pointing out their falacies more than once; instead, keep pressuring them for arguments, but do not waste your time reading (or writing!) lengthy posts (because after all, no amount of lying will be enough to change reality).
Insults may be used if the Malesheikist attempts to make you feel stupid for not accepting their dogmatic views. Remember, it's ok to be arrogant when you're right!

And if YOU'RE a Malesheikist... tsk tsk, shame on you. Of course, I'm always open minded. If you have some argument that isn't already addressed and thoroughly destroyed here or in the comments below, I will be glad to go over why it's wrong, and add it to this list. However, if you simply reiterate what has already been addressed here, it is unlikely that you will be treated with any consideration or patience (same if you obviously haven't read at least the opening text).

I sincerely hope that you have found this scientific study informative and entertaining. Just remember that Sheik is Zelda, make no compromise, and you should be fine. It will surely be entertaining to see what kind of bizarre twisted logic the Malesheikists will come up with in their attempt to discredit this study.
Take care!