While sexual orientation is about being emotionally or romantically attracted to other people, “gender identity” describes a person’s own internal feelings of being male or female (masculine or feminine); or a blend of both or neither (genderqueer). A person’s gender identity can be the same or different from their biological sex assigned at birth. In addition, people who are “gender dysphoric” may feel strongly that their true gender identity differs from the biological sex assigned to them at birth. In simpler terms, sexual orientation is about who we want to be with romantically or sexually. Gender identity is about who we feel we are, how we choose to express those feelings, and how we wish to be perceived and treated by other people. According to the most recent medical and psychological research, the feelings of emotional, romantic, and sexual attraction that eventually form adult sexual orientation usually emerge between ages 6 and 13. However, feelings of attraction can develop and change at any age, even without any prior sexual experiences. For example, people who practice celibacy or abstinence from sex are still aware of their sexual orientation and gender identity. Gay, lesbian, and bisexual people may follow different timelines in determining their sexual orientation than heterosexual people. Some decide they are lesbian, gay, or bisexual long before actually having sexual relationships with others. On the other hand, some do not determine their sexual orientation until after having had sexual relationships with persons of the same sex, opposite sex, or both. As the APA points out, discrimination and prejudice can make it hard for lesbian, gay, and bisexual people to accept their sexual orientation identities, thus slowing the process. It is not uncommon for people to be unsure of their sexual orientation. Some people live their entire lifetimes without ever becoming certain of their exact sexual orientation. Psychologists emphasize that “questioning” one’s sexual orientation is neither uncommon nor a form of mental illness. The tendency for feelings of attraction to shift throughout one’s life is known as “fluidity.” Few questions in the history of clinical psychology have been as deeply debated as what causes an individual’s sexual orientation. While scientists generally agree that both nature (our inherited traits) and nurture (our acquired or learned traits) play complex roles, the exact reasons for the various sexual orientations remain poorly defined and even less well understood. Despite years of clinical research on the question, no single cause or reason for developing a particular sexual orientation has been identified. Instead, researchers believe that each person’s feelings of emotional attraction are influenced by a complex combination of genetic dominance, hormonal, social, and environmental factors. While no single factor has been identified, the possible influence of genes and hormones inherited from our parents indicates that the development of sexual orientation may begin before birth. Some studies have shown that exposure to their parents’ attitude toward sexual orientation might affect how some children experiment with their own sexual behavior and gender identity. It was once believed that gay, lesbian, and bisexual sexual orientations were types of “mental disorders” often caused by sexual abuse during childhood and troubled adult relationships. However, this has been shown to be false and based mainly on misinformation and prejudice against so-called “alternative” lifestyles. The most recent research shows no relationship between any of the sexual orientations and psychological disorders.