Scientists have found that men have less pain and less effective pain relief after undergoing the same surgery and taking the same painkillers than women. This passage means:. ['Some painkillers work only for women and not for men.', 'Compared to women, post-operative men feel pain faster after taking the same painkillers.', 'Men are less capable of enduring pain than women.', 'The same painkillers are better for women than for men.']