A study by researchers at the Karolinska Institute in Stockholm, Sweden used brain scans to examine the brains of homosexual and heterosexual men and women. The study found that gay men and straight women had similar, symmetrical brains. The media have widely cited the study as potential evidence that sexual orientation may be biological. However, the Karolinska researchers have called the study, which looked at the brains of 90 individuals, far from conclusive and called for additional studies.