研究表明同性行为与遗传有关 但与基因无关

homosexual –adj. a person sexually attracted to people of the same sex

gay –adj. describing a homosexual person

participant –n. a person who is involved in an activity, event or study

lesbian –n. a woman who is sexually attracted to women

glimpse –n. a brief or quick view or look

origin –n. the point or place where something starts

twin –n. either one of two babies who are born at the same time to the same mother

sample –n. a small amount of something that give information about what it was taken from