Your spirits won’t be high after reading this. A growing body of research suggests a controversial, increasingly common habit in the US may be quietly damaging men’s sperm — and doubling their partners’ risk of miscarriage. “It is one of the most moveable factors right now in this country for improving fertility outcomes,” Dr. Natalie Crawford, a reproductive endocrinologist, said on a recent episode of the “ Huberman Lab ” podcast.  Across the nation, 24 states and the District of Columbia