A study conducted by Federal University in Rio de Janeiro found that women have more brain cells located in the olfactory bulb, which is responsible for a person's sense of smell, which means women could have a stronger sense of smell than men. Studies throughout the years have tried to prove why women have a keener sense of smell than men, with results being mixed or not concrete enough for a scientific explanation.
The study conducted in Brazil was performed by studying the brains of deceased men and women. Researchers concluded that since the women's brains had more cells in the olfactory bulb, and the brain doesn't produce many cells as a person ages, that the women were born with more cells. The study does not answer why women have a keener sense of smell or if there's a biological purpose for it.