Origins of Hutu, Tutsi and Twa adults has a high capacity for lactose digestion, a surprisingly high number for an agrarian people, which Mamdani suggests may be the result of centuries of intermarriage with Tutsi. Bethwell Ogot in the 1988 UNESCO "General History" further notes that the number of pastoralists in Rwanda increased sharply around the fifteenth century. Although Luis et al. (2004) in a more general study on bi-allelic markers in many African countries found a statistically significant genetic difference between Tutsi and Hutu, the overall difference were not large. Modern-day genetic studies of the Y-chromosome generally indicate that the Tutsi, like the Hutu, are
Rape during the Rwandan genocide during the genocide. Although Tutsi women were the main targets, moderate Hutu women were also raped during the genocide. Along with the Hutu moderates, Hutu women who were married to Tutsis and Hutu women who hid Tutsis were targeted. In a testimonial, Maria Louise Niyobuhungiro recalls seeing local people and Hutu men watched her get raped up to five times a day, and that when she was kept under watch by a woman, she received neither sympathy nor help and was also forced to farm between rapes. Tutsi women were also targeted with the intent of destroying their reproductive capabilities.