Ivy League sperm: Do you have it?

Now that fertility treatments have become big business, sperm banks have become very discriminating. Harvard accepts about nine percent of applicants. One big sperm bank says it takes donations from fewer than one percent of its 18,000 applicants.

Talk about swimming upstream.

And there's a lot more about sperm banks and donor sperm that might surprise you. Keep clicking to read some fascinating facts assembled by Dr. Randi Hutter Epstein, the author of a new book entitled "Get Me Out: A History of Childbirth from the Garden of Eden to the Sperm Bank."

Brains and personality matter

To become a sperm donor, a guy must have lots of fast-swimming, well-formed sperm. But that's not all he needs. Potential donors are also judged on their personality and intelligence. It helps if you're an Ivy Leaguer (though being a sperm donor probably won't impress the admissions committee at Yale). If you've been rejected by a sperm bank, there's little chance applying again will do the trick. And rejects never find out why they didn't make the cut.

Looks matter too

The ideal sperm donor stands six feet tall and has blond or brown hair, blue or green eyes and a "medium" complexion. Dimples? They're a plus, says Dr. Cappy Rothman, medical director of California Cryobank. Guys who are under 5'9'' are often rejected - though short men of Italian descent have been accepted as donors. It all depends on what women are looking for.

Middle-aged? You can forget about becoming a sperm donor. Sperm banks generally want guys between 19 and 39 years of age.

One of millions and millions

It takes only one sperm to fertilize an egg. But to be accepted as a sperm donor, men generally must have above-average sperm quantity - about 300 million to 400 million sperm cells in each ejaculation. The average guy can muster only about 200 million sperm per ejaculation.

Lucky for sperm donors, the male body is a sperm-making machine. In fact, once he hits puberty a guy churns out sperm every day of his life. Each sperm cell takes about 64 days to make.

GPS for gonads

The fertilization process is a bit like dating, only on a microscopic scale. And most of the little "guys" trying to score are so inept that they never make it anywhere near first base. They straggle. They go the wrong way. And even the best sperm are painfully slow. In fact, they swim about 30 micrometers per second, meaning it would take them 10 minutes to swim across the period at the end of this sentence.

On the other hand, sperm aren't completely clueless. Recent research indicates that each sperm cell has a chemical receptor that helps guide it to the waiting egg. Think GPS for the gonads.

$1,200 an hour?

How much do sperm donors make? About $100 per donation. And two donations per week for about a year are generally expected. While that's no windfall, it's not bad as an hourly rate - $100 for five minutes of "work" translates into $1,200 an hour.

Sperm on ice

Sperm doesn't stay fresh long, so sperm banks freeze the little guys. Since 2005, the FDA has required all frozen sperm to be tested for HIV-AIDS and other diseases. And to get the seal of approval from the American Association of Tissue Banks, sperm banks must test sperm for genes for Tay-Sachs disease, thalassemia, sickle-cell trait, and cystic fibrosis (if family history suggests a risk). In addition, each donor must provide at least three generations of family history to be evaluated by a geneticist.

Sperm outlive us

Can dead guys become dads? Absolutely. One California Cryobank client gave birth to a daughter four years after her husband had died. (His sperm had been collected immediately after his death.) Experts say sperm survives for about 48 hours after death.

Shopping for sperm

You can view hunky sperm donors on the web, but the men pictured are stand-ins for the real donors. Some banks have "personal shoppers" who listen to what the client wants and then sort through the samples to find Mr. Right. To preserve donor privacy, sperm bank clients generally are not permitted to view donor photos or get too much personal information about donors (though some donors provide hand-written essays that can be analyzed). But women can provide a photo to give the sperm bank an idea of the kind of man she'd like to be the father of her baby.

What religion says

Religious faith sometimes complicates the sperm donation process. For example, while Orthodox Judaism permits the use of donor sperm, orthodox rabbis often prefer that Jewish women use sperm from non-Jewish men. Why is that? Sperm from gentile donors cuts the risk that the resulting child might unwittingly grow up to marry a half-sibling (rabbis assume that offspring will marry within the faith). Jewish tradition holds that any child born to a Jewish mother is Jewish - so the sperm donor's religion doesn't matter.

Face in the crowd

How many people can trace their roots to a sperm bank freezer? No one seems to know. The last time anyone tallied the number of ampules of sperm collected or the number of babies born from donor sperm was in 1988, when the now-defunct Office of Technology Assessment estimated that 30,000 babies were born from donor sperm between 1986 and 1987. Dr. Rothman estimates that in the last three decades, sperm provided by California Cryobank has been used to create enough people who fill Madison Square Garden twice.

What's in a sperm?

Just what is a sperm cell? It's essentially a blob of DNA with a tail. Centuries ago, doctors thought each sperm contained a "homunculus" - a sort of miniature human eager to head to the fertile "soil" of the womb.