Why have more men chosen to freeze their sperm?

Facebook and Apple recently announced they would cover the $10,000 cost for egg harvesting and freezing for any female employees who wish to delay child-bearing for years or decades, but the cheaper perk of sperm banking isn’t offered to male workers who want to put off fatherhood.

Reproductive health specialists have debated whether young men really benefit from freezing youthful sperm to use later on, but some men have decided to shell out the money after hearing about research suggesting that sperm from a 40-year-old man could have DNA defects.

For example, a 2012 study published in the journal Nature found that older dads may play a bigger role in passing on mutations that lead to developmental problems, such as autism and schizophrenia. While a young 25-year-old father passes along an average of 25 new mutations to his child via his sperm, a 40-year-old transmits 65 mutations. Moms, on the other hand, transmit an average of 15 new mutations regardless of their age, the Icelandic researchers found.

“Collecting the sperm of young adult men and cold-storing it for later use could be a wise individual decision,’’ University of Michigan evolutionary biologist Alexey Kondrashov wrote in an editorial that accompanied the study.

Some men have acted on that advice.

“We are definitely seeing more men in their late 20s and early-mid 30s looking to bank sperm due to age,” said Grace Centola, laboratory and tissue bank director at the New England Cryogenic Center in Newton.

About 3 percent of the 1,000 or so men each year who pay $350 to process and freeze their sperm at the facility — plus $425 each year to store the vials — report on their paperwork that they’re doing so for age-related reasons, Centola said. But the number choosing to do so has been doubling every year since 2007. These men are 44 years old on average and don’t currently have a romantic partner. (The questionnaire doesn’t ask about sexual orientation.)

Dr. Hal Danzer, a reproductive endocrinologist and co-founder of Southern California Reproductive Center, said he’s seen an increase in patients who have decided to bank their sperm to preserve their fertility.

“Freezing sperm is good for men if they are going to delay having a family or in the case where a man is having a second family,” Danzer said. “There’s no real downside for doing this, as it is relatively inexpensive as well.”

Other fertility specialists disagree. “It’s really kind of crazy in my view because the incidence of autism and schizophrenia goes up only by a tiny amount as men age,” said Dr. Robert Oates, a urologist who treats male infertility at Boston Medical Center.

In a 2006 study published in the Archives of General Psychiatry, researchers from Mt. Sinai School of Medicine found that Israeli children born to men in the military who became a father at 40 or older were nearly six times as likely to be on the autism spectrum than those born to fathers who were younger than 30. But the absolute risk for older fathers remained low — less than 1 percent — since the overall incidence of autism in the children studied was only about 1 in 1,000.

Unlike eggs which lose their viability as a woman ages beyond 35, sperm, which are continuously produced by a man’s body, can remain hardy and capable of fertilizing an egg throughout a man’s lifetime. Oates said it’s also not clear whether sperm preserved in liquid nitrogen by a 25-year-old can remain healthy and intact if that man decided he wanted to become a father at age 60.

“The damage that may have occurred to sperm and the cost that a man incurs paying a sperm bank over 35 years seems to be completely out of balance with any increased risks of developmental disorders,” Oates said.

The American Society for Reproductive Medicine does not recommend freezing either eggs or sperm purely for delayed childbearing purposes, though it did issue a statement last year saying that egg cryopreservation should no longer be deemed experimental. While sperm have been successfully stored in liquid nitrogen since the 1970s, eggs, which are more fragile, have been harder to freeze and thaw, and researchers worked for years to perfect the preservation technique.

“At present time, we don’t know what fertility benefits eggs can offer when frozen long term,” said Dr. Rebecca Sokol, president of the American Society for Reproductive Medicine. “While frozen sperm can be used years down the road, they’re simply not as fertile and functional as freshly ejaculated sperm.”

When she gets the occasional phone call from a male patient asking whether he should bank his sperm for future use, she said she usually advises him not to spend the money if he’s healthy and has a normal sperm count.

There are, though, valid reasons for freezing sperm, she said, such as men with cancer getting treated with radiation or chemotherapy that could cause lasting infertility. Insurance frequently covers sperm banking for this purpose just as it covers egg freezing for female cancer patients facing infertility from their treatments.

Soldiers shipping off to a war zone may also be good candidates for sperm freezing, though that’s not routinely covered by insurance. “I encourage soldiers to bank their sperm,” Sokol said, “because certain blast injuries or chemical exposures have caused infertility in some veterans who have returned.”

Dr. John Petrozza, chief of the reproductive endocrine and infertility service at Massachusetts General Hospital, said he’s also discussed sperm banking with men about to undergo vasectomies. “They may not know what will happen or how they’ll feel about having children five to seven years down the road,” he said, so they decide to hedge their bets.