The word "intersex" has made headlines this week as Belgian model Hanne Gaby Odiele announced Monday that she was born with the condition.

Odiele, 29, is one of the first high-profile people to speak out about what it is like to be intersex. But what does being intersex mean?

Here are five things to know about being intersex:

1. According to the Intersex Society of North America (ISNA), "intersex" is a term used for a variety of conditions in which a person is born with a reproductive system or anatomy that doesn't conform to a typically male or female body. An example would be a girl who, like Odiele, is born with internal, undescended male sex organs, or a boy born with an exterior anatomy that more closely resembles that of a girl.

2. Being intersex is different from a person's gender identity. According to the United Nations, being intersex relates to biological sex characteristics, not sexual orientation. An intersex person can identify as straight, gay, lesbian, bisexual or asexual. That person can also identify as male, female, both or neither.

3. Experts estimate that between .05 percent and 1.7 percent of the population is born with intersex traits. The upper estimate is similar to the percentage of the population born with red hair.

4. Intersex traits are not always visible at birth, the UN reports. For some people, their traits do not show up until puberty or later. Some adults learn that they are intersex when they try to have children and find out that they can't, while others may never find out. Some intersex people have chromosomal variations that are never physically apparent.

5. New York last month became the first state to issue an intersex birth certificate. Sara Kelly Keenan, a 55-year-old woman born there, found out as an adult that she was born with male genes but a mix of male and female reproductive organs. According to NBC News, she was considered a boy for the first three weeks of her life before she was issued a new birth certificate that read "female." Her birth certificate now reads "intersex."