Final answer:
Rushton's genetic similarity theory implies that individuals are more attracted to those genetically resembling themselves, which is supported by kin selection and the good genes hypothesis within the context of natural selection.
Step-by-step explanation:
Rushton's genetic similarity theory suggests that people will be more attracted to those who resemble them genetically. This theory aligns with observations in natural selection and sexual selection, where organisms tend to favor those who are similar to themselves. Referred to as kin selection, it's a form of natural selection that promotes behavior favoring the reproductive success of an organism's relatives, possibly at the cost of the organism's own survival and/or reproduction.
There are different hypotheses explaining why certain traits are selected for, including the good genes hypothesis where organisms with desirable traits are selected as mates because those traits are an honest signal of genetic superiority. These behaviors and selections help increase the chances that copies of one's own genes will be passed to the next generation. Thus, while altruistic behaviors may appear detrimental to the individual's survival, they contribute to the genetic success of closely related peers, hence validating this evolutionary strategy.