The human species is not threatened by a shrinking population the last time I checked.
Get enough of them on the Western SADS diet and keep dumping toxins into the environment and that will likely change. In 1960 a good sperm count was considered to be 120 million sperm per milliliter of seminal fluid. Anything lower than that and a man was considered to be only marginally fertile. These days, things have become so bad that a man is considered fertile if he has only 20 million sperm per milliliter of ejaculate!
Life is all about balance and ginseng and v!agra trumps tofu.
Try some DHEA in place of the v!agra. You might be pleasantly surprised. Interestingly, one of several positive side effects (depending on whether you are the male or the female partner, perhaps) reported for supplemental oleander extract is increased male libido.