boys do take years off their mother's life!

If your mother tells you that you are taking years off her life, she speaks the truth (if you are male)! Just see this Scientific American article - years are a bit of an exaggeration, but definitely a few weeks or months. Virpi Lummaa, an evolutional biologist, has found that "those who bore sons had shorter life spans than those who gave birth to daughters" and "the mothers of sons proved especially susceptible to endemic infectious disease". Jewish mothers certainly anticipated Lummaa's conclusion that, "Sons also are not as likely as daughters to stick around to help their mothers out later in life". : )