The following comes from a June 17 story in the New York Times.

Since the first American “test tube” baby was born in 1981, in vitro fertilization, at a cost of $12,000 or more per cycle, has grown to account for more than 1.5 percent of all United States births.

The embryos with the greatest chance of developing into a healthy baby are used first, and the excess are frozen; a 2002 survey found about 400,000 frozen embryos, and another in 2011 estimated 612,000. Now, many reproductive endocrinologists say, the total may be about a million.

Couples are generally glad to have the leftover embryos, backups in case a pregnancy does not result from the first tries.

“But if I ask what they’ll do with them, they often have a Scarlett O’Hara response: I’ll think about that tomorrow,” said Dr. Mark Sauer, of Columbia University’s Center for Women’s Reproductive Care. “Couples don’t always agree about the moral and legal status of the embryo, where life begins, and how religion enters into it, and a lot of them end up kicking the can down the road.”

There are no national statistics on what happens with these leftover embryos. As a practical matter, many sit in storage indefinitely, academic researchers say, either at fertility clinics or other facilities, costing $300 to $1,200 a year. A small percentage of people stop paying the storage fees and leave it to the clinic or facility to figure out what to do.

….Many couples see their embryos as virtual children, fertility doctors say, and the numbers willing to give them to another family are increasing. According to the American Society for Reproductive Medicine, donated embryos were used in 1,084 transfers in 2013, up from 596 in 2009. They are meeting a demand….

Some people, saying they were troubled to be destroying a potential child, have created their own disposal ceremony — or, in a procedure known as compassionate transfer, have had a doctor place the embryos in the womb of the woman who made them, at a time of the month when she will not become pregnant. A few families have transferred ownership of the embryos to their adult children.

Sometimes couples disagree about who has the right to use their embryos. The actress Sofia Vergara and her ex-fiancé Nick Loeb have been fighting over the frozen embryos they created, providing weeks of media fodder, including Mr. Loeb’s Op-Ed article in the New York Times. Some cases have landed in court, where there is little guidance or precedent for judges struggling with this new territory, and so far, little consistency in their rulings.

…. At Dr. Ernest Zeringue’s IVF clinic in Davis, Calif., a program he calls California Conceptions goes beyond embryo donation to embryo creation.

The clinic buys eggs and sperm from donors whose profiles are likely to have broad appeal — like those who are tall, thin and well educated — then combines them to make embryos that are doled out to three or four families. Both the donors and the would-be parents know the embryos will be used by multiple families

For $12,500, patients get three tries, from a different batch of embryos each time — and a money-back guarantee for those who do not achieve a 12-week pregnancy.

“Our clients are typically people at the end of the line in terms of having a baby,” Dr. Zeringue said. “We used to have a regular donor embryo program, but the waiting list kept getting longer and longer, and in six years, we had less than a dozen donors.”

The new program, he said, helps him meet the demand.

But when word of the program spread in 2012, some doctors and lawyers questioned whether it was ethical for a company to create embryos it would own until they were implanted in a patient. Others were troubled by the whiff of eugenics in the company’s looking for the most marketable sperm and eggs — or the possibility that the children could, unknowingly, meet and marry their siblings.

Some called it a Costco approach to fertility, with quantity discounts to keep costs down.

“Make no mistake, this is commodification,” Andrew Vorzimer, a Woodland Hills, Calif., fertility lawyer, posted in his blog. “These are not donated embryos. Rather, they are embryos created from donors hand-selected by California Conceptions. It is one step removed from a mail-order catalog. The only difference is that the product being sold is nascent human life….”