I read the following on the Born Different website:

if one twin is born gay, there is a higher chance (52%) that the other will be gay as well.

since identical twins share DNA, this tells us that genetics plays a part in sexual orientation

that means some people are born gay.

The first thing I ask when I see the above is this: “if one twin is born gay, there is a higher chance…than what?”  This is a comparison without giving a comparison.  Does it mean that of sets of identical twins where at least one person is a homosexual that 52% of these people are both homosexual while 48% of them are not?  This is how I would probably take the statement.

If that’s the case, then if one person is gay it’s a 50/50 shot as to whether the other would be gay.

50/50 when they have identical DNA is not exactly proof that DNA plays any role.  In fact, the 48% that aren’t both gay sort of disprove that notion that genetics plays that big of a role in it.

Furthermore, identical twins are (amazingly enough) virtually always in identical environments.  The only way that the above study could possibly have any scientific validity for the conclusion (that people are born gay), the identical twins that are surveyed must be identical twins separated at birth.

Since there are very few of them, even fewer of which have at least one person as a homosexual, there is no statistical certainty of that conclusion.