Gamete exchange

 Here's a cheerful story of peer to peer assisted reproduction, from the Washington Post:

Two couples couldn’t have babies, so they helped each other  By Kyle Melnick

"Neva and her wife, Kelsey, were considering using a surrogate or an in vitro method to have a child. John and his wife, Amy, couldn’t carry a pregnancy because of a hysterectomy Amy underwent to treat endometriosis.

“Just give us your sperm,” Neva recalled telling John. “We’ll have a baby, and then we’ll just give you an egg. It’s not a big deal.”

...

"In 2020, John donated sperm so that Kelsey could become pregnant through an insemination service. The Bentons’ baby was born the next year in Kansas. Kelsey, now 32, then acted as a surrogate for the Cardenases and birthed the Arizona couple’s child in July.

...

"the couples bought an insemination kit and wrote up a surrogacy contract with an attorney’s assistance. Kelsey tracked her menstrual cycles; John, who’s now 41, took pills and adjusted his diet to produce healthy sperm."