Xx chromosomes The pair of sex-differentiating chromosomes that leads to someone being born with a vagina, vulva, uterus, and ovaries. Babies with xx chromosomes are usually assigned female at birth. Related Articles: Intersex: Brought to AttentionAbout 1.7% of the population is born into the term intersex and to put the number in perspective, the same number of people are born with red hair.Glossary: FemaleGlossary: Sex chromosomes Xe (xe, xem, xyr, xyrs, xemself) Xy chromosomes