LOS ANGELES

DANIEL E. GURR, a doctor in Miami, had always wanted a baby. The yearning lasted through his 30s and early 40s, through medical school and into his residency. That longing created tension; he and his longtime boyfriend, he said, fought each time the subject came up.

At 46, Dr. Gurr, who is settled in his job but now unattached, is finally fulfilling his wish. Next month, through a surrogate, he will become the single parent of a baby boy.

“I’ve always felt that I wanted fatherhood to be a part of my life,” he said. “It’s just a core part of who I’ve always been. I absolutely would want a partner, but I couldn’t let my life wait for that random event.”

Like the women two decades ago who decided to become mothers on their own  sparking a redefinition of family, not to mention a culture war  single men, gay and straight, hear the ticking biological clock. And they are moving beyond looking for Ms. or Mr. Right.