Microscopic photo of intracytoplasmic sperm injection.

A startup called Darwin Life says it will use a controversial fertility technique to help forty-somethings get pregnant for $100,000.

A U.S. fertility doctor has started a company with a provocative vision for older women: become pregnant by having their DNA shifted into a young woman’s egg.

The company, Darwin Life, was quietly established last year by John Zhang, also founder of a New York City clinic called New Hope Fertility Center, to deploy a cutting-edge fertility technology called “spindle nuclear transfer.”

Originally developed as a way to prevent women from passing certain rare diseases on to their children, Zhang says it can also be used to create rejuvenated eggs. He calls it a “cure for infertility” and says Darwin Life will begin offering it to women aged 42 to 47, an age at which the chance of becoming pregnant declines dramatically.

Zhang is a highly skilled fertility provocateur who last year, in Mexico, carried out the first successful use of the technique, which employs delicate hollow needles to swap the chromosomes of a woman’s egg into the egg...