When people of different sexes appear together, they will think about how to show themselves in front of each other and attract each other's attention. Homosexual attraction means that people of the same sex are easy to compare with each other when they appear together.
There is often a subtle competitive relationship between the same sex, sometimes regardless of age, just like a boy secretly envied his father when he was young and set himself a stronger goal than his father. On the contrary, girls will envy their mothers for their good looks.
However, back in real life, there are both same-sex attraction and opposite-sex repulsion, and jealousy will also occur between opposite-sex. Sometimes it may be because my sister has one more lollipop than my brother, and I am jealous or dissatisfied by my brother. There are more similar things.