A research study demonstrates in mice the biological relevance of sex in the effects of accelerated ageing caused by a chronic treatment of D-galactose, a sugar found abundantly in milk and to a lesser extent in fruits and vegetables. At high doses, this substance accelerates ageing in males, affecting them at sensory and motor level and in their neuro-immuno-endocrine system, while females experience alterations in learning and their ability to register information about their surroundings and orientation. However, at low doses the treatment has positive effects, especially in males.