Since the 1990s, several studies involving French centenarians have shown a gender paradox in old age. Even if women are more numerous in old age and live longer than men, men are in better physical and cognitive health, are higher functioning, and have superior vision. If better health should lead to a longer life, why are men not living longer than women? This paper proposes a hypothesis based on the differences in the generational habitus between men and women who were born at the beginning of the 20th century. The concept of generational habitus combines the generation theory of Mannheim with the habitus concept of Bourdieu based on the observation that there exists a way of being, thinking, and doing for each generation. We hypothesized that this habitus still influences many gender-linked behaviours in old age. Men, as "oaks," seem able to delay the afflictions of old age until a breaking point, while women, as "reeds," seem able to survive despite an accumulation of health deficits.