Men wear Tilak after performing a religious ceremony. It is auspicious for men to wear that on thier forehead. Most men who wear it, tend to wear it everyday. Others wear only after certain specific festivals.
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Name : Chip, City : Philly, State : PA Country : United States,  I'm not sure why they are doing it now, below is an exerpt from a website (http://www.hinduonnet.com)...In the earlier times, besides the priests, some men applied the tilak on their forehead on special occasions like a battle, a hunt or other important events when the mother/ wife used to smear it on the man's forehead before he set out on his mission.
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Name : Mike, Gender : M, Sexual Orientation : Straight, Race : White/Caucasian, Religion : Catholic, Age : 37, City : East Bangor, State : PA Country : United States, Occupation : System Engineer, Education level : Technical School, Social class : Upper middle class,  I'm not an expert on this, but from what I've heard and read on this, The red dot worn on the forehead of Indians has very little to with marital status or sex. The religion that they practice believes that everyone has three eyes: The physical pair that we are born with and the third eye which is like a doorway into one soul, so to speak. This red dot respresents this third eye. Over time, most men have stopped wearing the red dot. Nowadays the women who wear it might wear a red or a black dot in ways to show marital status. This infomation is what I have gathered from my readings.
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Name : KIM, Gender : F, Sexual Orientation : Straight, Religion : African Methodist Episcopalian, Age : 33, City : MONTEREY, State : CA Country : United States, Occupation : Army, Education level : 2 Years of College, Social class : Lower middle class,  Since I lived in India a few years back, I know that they do it on special occasions and also if they are more religious and more old-fashioned.
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Name : Gaveem, Gender : M, Sexual Orientation : Straight, Race : Asian, Religion : Muslim, Age : 19, City : Malé, State : NA Country : Maldives, Occupation : Operations Assistant, Education level : High School Diploma, Social class : Middle class,  It's a sign of their devation to their faith. The same applies to women...although in their case it CAN mean that they are married...but not always. The dot has many names: bindi, tika etc.
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Name : Tom24105, City : Calumet City, State : CA Country : United States,  The idea behind the tilak is that you are worshiping the soul, it is not gender biased, its just that many men choose not to put on the tilak and therefore there is a misconception that only women do it.
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Name : Neil, Gender : M, Sexual Orientation : Straight, Race : Asian, Religion : Hindu, Age : 24, City : Springfield, State : VA Country : United States, Occupation : Student, Education level : 4 Years of College, Social class : Middle class,  Its a religious thing as well..
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Name : Boo, City : Singapore, State : NA Country : Singapore,  Often men wear it during religious events as well though it is not as common. Both men and women wear these 'teekas' but for women it's more an issue about vanity and fitting the 'female role'. Men on the other hand, don't care, or have to be modern looking to fit in a modern society.
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Name : Nick20018, City : BC, State : NA Country : Canada,  Its a religious thing. Mostly worn on religious occasions or at the temple. Some may wear after prayer in the morning or evening, on a regular basis.
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Name : Doesnt-Matter, Gender : M, City : xxxx, State : NJ Country : United States, Education level : Over 4 Years of College, Social class : Upper class,  Such 'tilak'are usually worn by Hindu people. Both men and women can wear them.
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Name : lopnore22571, City : wichita, State : KS Country : United States,  It's to symbolise the 'third eye' awareness, as practised by Hindus. Gender has nothing to do with the red dot, and neither does marriage.
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Name : Natali, Gender : F, Sexual Orientation : Bisexual, Race : White/Caucasian, Religion : Atheist, Age : 20, City : Vancouver, State : NA Country : Canada, Occupation : Writer, Social class : Lower middle class,  You are very right, its is infact called 'Tilak' and is called by this name only when it is on a Man's forhead. Sometimes it is also called 'tika' in northern part of India. 'Tilak' is usually applied as sign of God's blessing during a customary ceremony. Many times during a temple visit, the priests, apply Tilak on Men's forehead for blessings. It is considered holy and pious in a way. Going back in history, women used to apply 'Tilak' on their Husband, brothers, Father's forehead to wish them victory, when these men leave home for battle front.
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Name : Vikas-Rai, Gender : M, Sexual Orientation : Straight, Race : Asian, Religion : Hindu, Age : 34, City : South Br, State : NJ Country : United States, Education level : Over 4 Years of College, Social class : Middle class, 
CSParticipant
dURING RELIGIOUS HOLIDAYS SOME MEN DO INFACT PLACE A RED DOT ON THEIR FOREHEAD TO SIGNIFY THAT THEY HAVE DONE THEIR PRAYERS. IT IS NOT UNLIKE ASH WED. FOR CHRISTAINS. ALSO, USED BY CERTAIN RELIGIOUS SECTS AS A SIGN OF PRIESTHOOD.
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Name : CS, Gender : M, Sexual Orientation : Straight, Race : White/Caucasian, Religion : Sikh, Age : 37, City : SCOTTSDALE, State : AZ Country : United States, Occupation : SALES, Education level : 4 Years of College, Social class : Middle class,  Religious and traditional Indian men, mostly from South India, perform a small prayer after their daily morning bath/shower. As part of this ritual they may wear a 'Tilak' on their head. Not sure of the significance of this though.
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Name : Samit, Gender : M, Race : South Asian, Religion : Hindu, Age : 31, City : Redmond, State : WA Country : United States, Education level : Over 4 Years of College,  Tilak is not obligatory for everyone. Usually devoted Hindus mark the tilak on their foreheads before their daily religious rites although I have come across people who mark the tilak after prayers.this applies to both men and women. The Red Dot for women is called a Bindi you can learn it's history here: http://www.shaadi.com/wedding/rituals/bindi/040306-bindi-history.php
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Name : Ajeet Mehra, Gender : M, Sexual Orientation : Straight, Race : Asian, Religion : Agnostic, Age : 49, City : Taipei, State : NA Country : Taiwan, Occupation : Businessman, Education level : High School Diploma, Social class : Middle class,