Which is an internal factor that may influence one’s decision to have sex?

Desire for emotional intimacy:

Both other choices involve external factors. Your partner’s religious believes are something you cannot control or have insight on. And your parental influence reflects their want, not the individual’s. Desire for emotional intimacy is the only one here that is owned and influenced internally by the individual

Explanation:

While desire for intimacy are factors, it can also be peer pressure, or pressure from the partner to engage in any sexual activity, or mutual desire. Even foreplay can " accidentally " lead up to it, seeing that some get carried away in the emotional whirlwind.

there are men and women, some choose to be both or change their gender. often times those people go by "other". those who change their gender are known as "transgender"