Not true: Multiple publications exist showing a detriment to sperm motility, and morphology (shape) associated with smoking. Other more subtle effects such as sperm agglutination (sticking together) or the presence of leukocytospermia (white blood cells in the semen) have been associated with smoking. Quitting smoking is generally not only a good idea for your health, but also for your fertility.
Not true. Both men and women are designed to be fertile after puberty. After that, well, let’s just say that no one grows younger. Although for women there is a much more rapid decline in fertility as they proceed from their thirties into their forties, for men there is also a decline in sperm quality. Sperm banks generally do not accept sperm donors over the age of 44. Yes, some men will conceive a child at a later age, but their fertility is still likely not as good as it was in years prior.
Well, sort of. The testes keep sperm producing cells about two degrees cooler than core body temperature and exposure of the testicles to heat for a prolonged period may impact sperm production. But there have been no convincing studies that undergarments affect anything and even one study that showed temperature of the testicles was independent of boxers versus briefs. I tell patients to wear whatever they are comfortable in. However, prolonged and regular visits to a hot tub, where the testicles are immersed in hot water may not be a good idea. Similarly, working with a laptop on your lap, exposing your testicles to heat radiation for a prolonged period may also be something to avoided. Place something between you and that computer.
Sometimes. Many overweight men have no problem with conception; however, once “overweight” progresses to “obese” or “morbidly obese”, many things change. Obesity has become epidemic in the US and it is associated with multiple health problems including diabetes, high blood pressure, heart disease, and also male infertility. Obesity is also associated with sleep apnea and the two conditions put men at risk for lower testosterone levels, higher estrogen levels and worse sperm production.
If lifestyle includes how much and how often you indulge, it sure can. Excess alcohol and marijuana can drive sperm count down. This does not mean you need to abstain from all celebratory substances all the time. The saying everything in moderation is the correct choice, here. A glass of wine, a beer, for most people is no problem; on the other hand, a keg is not going to serve your purposes well.
Over all, maintaining better health by eating a good diet, getting enough exercise and enough sleep, and avoiding things injurious to your body will serve your fertility well.
