user79: I have recently heard that the only 5% percent out of entire chess players are women. I find this suspicious. Who says that only men can play chess? Is this statistic true, and if it is, why?

user816: Despite all feminist claims, it's not cultural, but biological.  In countries where supposedly the culture is more supportive for equality in activities (like USSR), males are by far relatively predominant in chess, the same as in US.  It's the same with careers.  It hasn't made much of a difference now that engineering, for instance, has been a field accessible to women for a long time.  Most of them simply prefer social activities more.  As Desmond Morris says, the brains of men and women work differently from each other.  This doesn't imply any inferiority, simply there are activities more suited for men and activities more suited for women.  E.g. dyslexia is almost wholly an issue for men, not for women.

user672: Chess tends to impersonate war.
No one says women can't fight, but it's usually considered (culturally) as more of a men's activity, don't you think ?
I'm very curious about the “why” aspect myself, but that probably calls for much socio-psychology I'm not near knowledgeable enough at, and probably isn't even well known yet, not to mention far from the scope of this site.
For real statistics, I guess scripting over a FIDE ratings database wouldn't be too hard, probably even mentioned in the introductory section of Women in Chess.
Most people (and other answers) cite a 5-15% figure.

user4418: 
I have recently heard that the only 5% percent out of entire chess
  players are women.

In 2018 this is certainly false. The statistics from the November 2018 FIDE rating list are that there are 668785 active players of whom 99325 are female. That is a female participation rate of about 15%.
Update January 2020: The statistics from the January 2020 FIDE rating list are that there are 771484 active players of whom 120065 are female. That is a female participation rate of about 15.6%.
The statistics from the May 2012 FIDE list (when you wrote this question) are that were 87538 active players of whom 7226 were female. That is a female participation rate of 8.25%. So even when you wrote this question your number was inaccurate.
The big difference between May 2012 and today in FIDE rating terms is that the current figures also include rapid and blitz and also FIDE's online Arena for online chess. FIDE rating of rapid and blitz only started with the July 2012 list and has grown massively since then. I believe the FIDE online Arena only started in late 2015.
One other factor also affects the figures and that is that the FIDE default when a new player is recorded is male. If the registering federation does not specify sex then the player is registered as male. This obviously introduces distortions in the figures. It should be noted that FIDE has made great efforts in more recent times to clean up its data and correct errors. More recent FIDE data is more accurate than older data.
Now I don't know which federation you come from so your figure could be accurate for your federation even though it is inaccurate overall.
Figures vary wildly by federation and not necessarily in the way that you might imagine (unless you listen to Jordan Peterson). 
Looking at the female participation rate (100 x active female players / active players for federations with 100 or more active players) gives these 10 federations as bottom of the list from the May 2012 list -
Czech Republic - 4%
Spain - 3.9%
Sweden - 3.8%
Nepal - 3.4%
Italy - 3.3%
Finland - 2.6%
Belgium - 2.5%
Switzerland - 2.3%
Ireland - 2.1%
Denmark - 1.5%   
And here are the top 5 from the May 2012 list -
Vietnam - 39.1%
Georgia - 33.7%
China - 31.2%
Ecuador - 23.8%
Azerbaijan - 23.6%   
Here are the corresponding figures from the November 2018 list (restricted to federations with 1000 or more active players - about 10x as many active players so increase the "noise" filter by 10x).
First the bottom 10 -
Sweden - 6.3%
Israel - 6.3%
Switzerland - 5.9%
Argentina - 5.3%
Netherlands - 4.8%
Norway - 4.8%
Finland - 4.4%
Ireland - 4.2%
Denmark - 2.7%
Libya - 0.9%
And the top 5 -
Mongolia - 41.9%
United Arab Emirates - 35.6%
Sri Lanka - 34.0%
Vietnam - 32.5%
Malaysia - 28.3%   

Who says that only men can play chess?

Nobody says that and the statistics certainly don't say that either. What they do suggest is that men want to play chess much more than women. Where women have a greater choice of what sort of things they can do, as in the Scandinavian countries, it appears that many more of them have better things to do with their time than play chess ;-).
PS It's a shame there isn't an international knitting federation publishing data we could use to extract male participation rates in knitting.
NB For anybody interested in the raw data, FIDE publish rating file data going back to 2001. For data before 2001 there is the Olimpbase site, but their data is very "dirty" and will need a lot of work to eliminate/merge duplicates and correct obviously false data before it can be used.

user70: I don't know that it's 95%, but it's close.
Why aren't there more female players?  Probably a combination of things certainly including cultural gender bias.  Women can surely play the game but American culture doesn't seem to reward them for it.
In about 1990, my B-player rating would have put me in the top 50 women players in the country.  A little later, the US got a lot of immigration from ex-Soviet Bloc countries.  This included a very good number of strong female players.  I can only surmise that their cultures were more supportive of the women. 
Further, I feel the game was invented as a war game by men for men and as such probably has a certain character that is best appreciated by men.
Compare to Go, a game of remarkable complexity, which has a much higher level of female participation.

user3270: Among active players in the United States, about 15% seem to be women.
If you look at the rankings on this page, there are currently 9513 women active out of 64634 total players. That's 14.7%.
My guess is that the composition of female players skews more heavily towards juniors than the composition of male players, but I didn't find any numbers on that. I say this because I saw more female players at scholastic tournaments as a child than I do now at open tournaments as an adult.

79: <p>I have recently heard that the only 5% percent out of entire chess players are women. I find this suspicious. Who says that only men can play chess? Is this statistic true, and if it is, why?</p>
 816: <p>Despite all feminist claims, it's not cultural, but biological.  In countries where supposedly the culture is more supportive for equality in activities (like USSR), males are by far relatively predominant in chess, the same as in US.  It's the same with careers.  It hasn't made much of a difference now that engineering, for instance, has been a field accessible to women for a long time.  Most of them simply prefer social activities more.  As Desmond Morris says, the brains of men and women work differently from each other.  This doesn't imply any inferiority, simply there are activities more suited for men and activities more suited for women.  E.g. dyslexia is almost wholly an issue for men, not for women.</p>
 672: <p>Chess tends to impersonate <strong>war</strong>.<br />
No one says women can't fight, but it's usually considered (culturally) as more of a men's activity, don't you think ?</p>
<p>I'm very curious about the “why” aspect myself, but that probably calls for much socio-psychology I'm not near knowledgeable enough at, and probably isn't even well known yet, not to mention far from the scope of this site.</p>
<p>For real statistics, I guess scripting over a FIDE ratings database wouldn't be too hard, probably even mentioned in the introductory section of <a href="https://rads.stackoverflow.com/amzn/click/com/0899502326" rel="nofollow noreferrer" rel="nofollow noreferrer"><em>Women in Chess</em></a>.<br />
Most people (and other answers) cite a 5-15% figure.</p>
 4418: <blockquote>
  <p>I have recently heard that the only 5% percent out of entire chess
  players are women.</p>
</blockquote>

<p>In 2018 this is certainly false. The statistics from the November 2018 FIDE rating list are that there are 668785 active players of whom 99325 are female. That is a female participation rate of about 15%.</p>

<p><strong>Update January 2020</strong>: <em>The statistics from the January 2020 FIDE rating list are that there are 771484 active players of whom 120065 are female. That is a female participation rate of about 15.6%.</em></p>

<p>The statistics from the May 2012 FIDE list (when you wrote this question) are that were 87538 active players of whom 7226 were female. That is a female participation rate of 8.25%. So even when you wrote this question your number was inaccurate.</p>

<p>The big difference between May 2012 and today in FIDE rating terms is that the current figures also include rapid and blitz and also FIDE's online Arena for online chess. FIDE rating of rapid and blitz only started with the July 2012 list and has grown massively since then. I believe the FIDE online Arena only started in late 2015.</p>

<p>One other factor also affects the figures and that is that the FIDE default when a new player is recorded is male. If the registering federation does not specify sex then the player is registered as male. This obviously introduces distortions in the figures. It should be noted that FIDE has made great efforts in more recent times to clean up its data and correct errors. More recent FIDE data is more accurate than older data.</p>

<p>Now I don't know which federation you come from so your figure could be accurate for your federation even though it is inaccurate overall.</p>

<p>Figures vary wildly by federation and not necessarily in the way that you might imagine (unless you listen to Jordan Peterson). </p>

<p>Looking at the female participation rate (100 x active female players / active players for federations with 100 or more active players) gives these 10 federations as bottom of the list from the May 2012 list -</p>

<p>Czech Republic - 4%<br>
Spain - 3.9%<br>
Sweden - 3.8%<br>
Nepal - 3.4%<br>
Italy - 3.3%<br>
Finland - 2.6%<br>
Belgium - 2.5%<br>
Switzerland - 2.3%<br>
Ireland - 2.1%<br>
Denmark - 1.5%   </p>

<p>And here are the top 5 from the May 2012 list -</p>

<p>Vietnam - 39.1%<br>
Georgia - 33.7%<br>
China - 31.2%<br>
Ecuador - 23.8%<br>
Azerbaijan - 23.6%   </p>

<p>Here are the corresponding figures from the November 2018 list (restricted to federations with 1000 or more active players - about 10x as many active players so increase the "noise" filter by 10x).<br>
First the bottom 10 -</p>

<p>Sweden - 6.3%<br>
Israel - 6.3%<br>
Switzerland - 5.9%<br>
Argentina - 5.3%<br>
Netherlands - 4.8%<br>
Norway - 4.8%<br>
Finland - 4.4%<br>
Ireland - 4.2%<br>
Denmark - 2.7%<br>
Libya - 0.9%</p>

<p>And the top 5 -</p>

<p>Mongolia - 41.9%<br>
United Arab Emirates - 35.6%<br>
Sri Lanka - 34.0%<br>
Vietnam - 32.5%<br>
Malaysia - 28.3%   </p>

<blockquote>
  <p>Who says that only men can play chess?</p>
</blockquote>

<p>Nobody says that and the statistics certainly don't say that either. What they do suggest is that men <em>want</em> to play chess much more than women. Where women have a greater choice of what sort of things they can do, as in the Scandinavian countries, it appears that many more of them have better things to do with their time than play chess ;-).</p>

<p>PS It's a shame there isn't an international knitting federation publishing data we could use to extract male participation rates in knitting.</p>

<p>NB For anybody interested in the raw data, FIDE publish <a href="https://ratings.fide.com/download.phtml" rel="nofollow noreferrer">rating file data</a> going back to 2001. For data before 2001 there is the <a href="http://www.olimpbase.org/index.html?http%3A%2F%2Fwww.olimpbase.org%2FElo%2Fsummary.html" rel="nofollow noreferrer">Olimpbase site</a>, but their data is very "dirty" and will need a lot of work to eliminate/merge duplicates and correct obviously false data before it can be used.</p>
 70: <p>I don't know that it's 95%, but it's close.</p>

<p>Why aren't there more female players?  Probably a combination of things certainly including cultural gender bias.  Women can surely play the game but American culture doesn't seem to reward them for it.</p>

<p>In about 1990, my B-player rating would have put me in the top 50 women players in the country.  A little later, the US got a lot of immigration from ex-Soviet Bloc countries.  This included a very good number of strong female players.  I can only surmise that their cultures were more supportive of the women. </p>

<p>Further, I feel the game was invented as a war game by men for men and as such probably has a certain character that is best appreciated by men.</p>

<p>Compare to Go, a game of remarkable complexity, which has a <em>much</em> higher level of female participation.</p>
 3270: <p>Among active players in the United States, about 15% seem to be women.</p>

<p>If you look at the rankings on <a href="http://www.uschess.org/msa/MbrDtlMain.php?12543137" rel="noreferrer">this page</a>, there are currently 9513 women active out of 64634 total players. That's 14.7%.</p>

<p>My guess is that the composition of female players skews more heavily towards juniors than the composition of male players, but I didn't find any numbers on that. I say this because I saw more female players at scholastic tournaments as a child than I do now at open tournaments as an adult.</p>
