IMPORTANT
By selecting specific age groups you are limiting your audience to only those with identified age. This is important because even if you select all options, age targeting can actually work against you.

An example:
100.000 people are potential viewers of a page.
8.000 of these are identified as 19 to 24.
5.000 are identified as 25 to 34.
5.000 are identified as 35 to 44.
1.000 are identified as 45 to 54.
800 are identified as 55 to 64.
200 are identified as 65 and over.
80.000 are not age identified.

Even if you select all age groups, you are still limiting your audience to only those with identified age. In this example it means your ad will only reach 20.000. Your ad will not be shown to the 80.000 who are not age identified.

If you wish to reach all 100.000, don’t select any age groups.

BOTTOM LINE
If you wish your ads to reach everyone, regardless age, don’t use Age Targeting.

IMPORTANT
By selecting Male and/or Female you are limiting your audience to people with identified gender. This is important because even if you select both options, gender targeting can actually work against you.

An example:
100.000 people are potential viewers of a page.
10.000 of these are identified as Male.
15.000 are identified as Female.
75.000 are not gender identified.

If you want your ad to be shown only to men or women, select Male or Female.

Now, if you want your ad to be shown to everyone, this is where is gets a little tricky. If you select both options Specific: Male and Female, you are still limiting your reach to an audience with identified gender. In this example it means your ad will only reach 25.000. Your ad will not be shown to the 75.000 who are not gender identified.

If you wish to reach all 100.000, don’t select specific genders.

BOTTOM LINE
If you wish your ads to reach everyone, regardless gender, don’t use Gender Targeting.