We are fast approaching Father’s Day, the festive occasion on which we plague Dad with yet another necktie or collect phone call and just generally strive to remind the big guy of the central verity of paternity — that it’s a lot more fun to become a father than to be one. “I won’t lie to you,” said the great Homer Simpson. “Fatherhood isn’t easy like motherhood.” Yet in our insistence that men are more than elaborately engineered gamete vectors, we neglect the marvels of their elaborately engineered gametes. As the scientists who study male germ cells will readily attest, sperm are some of the most extraordinary cells of the body, a triumph of efficient packaging, sleek design and superspecialization. Human sperm are extremely compact, and they’ve been stripped of a normal cell’s protein-making machinery; but when cast into the forbidding environment of the female reproductive tract, they will learn on the job and change their search strategies and swim strokes as needed.

Sperm are also fast and as cute as tadpoles. They have chubby teardrop heads and stylish, tapering tails, and they glide, slither, bumble and do figure-eights. So while a father may not be entitled to take the same pride in his sperm as he does in his kids, it’s fair to celebrate the single-minded cellular commas that helped give those children their start.

Sperm are pretty much the tiniest cells in the human body. The head of a mature, semen-ready sperm cell spans about 5 microns, or two ten-thousandths of an inch, less than half the width of a white blood cell or a skin cell. And a sperm cell is absurdly dwarfed by its female counterpart, the egg, which, fittingly or not, is among the biggest cells in the body. At 30 times the width of a sperm, the egg is massive enough to be seen with the naked eye.

But men have the overwhelming quantitative edge in the gamete games. Whereas current evidence suggests that a human female is born with all the eggs she will have, and that only about 500 of her natal stock of one million will ever ripen and have a shot at fertilization, a male from puberty onward is pretty much a nonstop sperm bakery. Each testicle generates more than 4 million new sperm per hour, for a lifetime total of maybe 12 trillion sperm per man (although the numbers vary with the day and generally slope downward with age).