Complex sentence: In 1992, Allen and Gorski reported a difference related to sexual orientation in the size of the anterior commissure, but this research was refuted by numerous studies, one of which found that the entirety of the variation was caused by a single outlier.
Split into simpler sentences: In 1992, Allen and Gorski reported a difference related to sexual orientation in the size of the anterior commissure. But this research was refuted by numerous studies, one of which found that the entirety of the variation was caused by a single outlier.