When examining the concordance rates of homosexuality between identical twins and fraternal twins or non-twin siblings,the following has been reported by research - if one identical twin is gay,his brother has a ___% chance of being gay as well.If a fraternal twin or a non-twin sibling is gay,his brother has a ___% chance of being gay as well.

Question

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Research has shown that if one identical twin is gay, there is about a 50% chance the other will be too. For fraternal twins or non-twin siblings, the chance drops to approximately 15%. This suggests a genetic component to sexual orientation, but also indicates that genetics do not fully determine this aspect of identity.

When Examining the Concordance Rates of Homosexuality Between Identical Twins