Detecting gender from first name

In an effort to detect as much as possible from as little as possible, so that we don't have to put the user through the pain of filling a long and boring registration form, we can currently detect the location with geolocation. What if we could also detect the gender, from the user's first name?

This is not 100% accurate, because in different cultures there is a possibility of both genders having the same first name, but it's an idea for a temporary solution. If you want to shave one more field from the registration form, but at the same time you need demographic statistics and can tolerate a small accuracy decrease, then you can detect the user's gender at registration, and let the user fill in the real gender later in the profile page. Therefore, you don't make the user jump through hoops to register, but you have a pretty good idea of the gender, even if it's not explicitly specified.

There's a great site about the etymology and history of first names that has compiled a pretty extensive list of first names from all cultures. You can find a list of feminine and masculine names at:

Having a thorough list of names, you can now create two separate serialized arrays, one with feminine and one with masculine names, then check if the user's specified first name falls in each category.

$femaleNames = unserialize(file_get_contents('femaleNames.dat'));
if (in_array($firstName, $femaleNames)) {
    $gender = 'f';
}

$maleNames = unserialize(file_get_contents('maleNames.dat'));
if (in_array($firstName, $maleNames)) {
    $gender = 'm';
}

To optimize the process, you can actually only look at one array, and determine that, if the name is not part of that array, then it must be from the other. This way, you can also have a default gender if the name is not in any array.

$gender = 'm';

$femaleNames = unserialize(file_get_contents('femaleNames.dat'));
if (in_array($firstName, $femaleNames)) {
    $gender = 'f';
}