Understanding Sexual Orientation

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Sexual orientation has been linked to genetic factors.

Not all identical twins have the same sexual orientation, though.

Epigenetics can help explain why two people can have the same genes, but different sexualities.

Differences in prenatal hormone exposure may be a key to understanding this phenomenon.

A growing amount of research suggests that sexual orientation has a genetic basis. If sexuality is genetically determined, this means identical twins should always have the same orientation, right? While that might seem like a logical conclusion, it's not true.

Identical twins sometimes have different orientations. For example, one may be straight while the other is gay. How can that be?

Same Genes, Different Attractions

In cases like this, it might be tempting to assume that both twins are actually gay, but one just hasn’t come out yet. In other words, maybe there isn’t a true discrepancy. However, science doesn't support this interpretation.

In a study where scientists looked at the sexual arousal patterns of identical twins with different sexualities (specifically, where one was gay and the other was straight), they found that gay twins demonstrated more genital arousal in response to same-sex images, whereas straight twins demonstrated more arousal in response to opposite-sex images.

This tells us that, while identical twins have the same genes, they don’t necessarily have the same sexual attractions.

Genetics Versus........

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