Erin Allday

The flu season hasn't kicked in yet, but infectious disease experts are on the alert for new strains of the virus, including another swine flu that's popped up in parts of the United States and a drug-resistant flu circulating in the Southern Hemisphere.

Since the 2009 swine flu pandemic, public health and infectious disease experts have upped their surveillance of new flu strains, and they're paying close attention to what's happening worldwide in hopes of being better prepared for the type of flu season that will hit here.

SAN FRANCISCO -- Last month Trent Arsenault got three women pregnant -- a new record for the Fremont man and father of 14 (and counting).

"I know the holidays are busy," Arsenault, 36, said with a chuckle, "but I didn't know that included babies."

Arsenault's been a sperm donor for five years, offering his semen to women he meets on the Internet for free.

But his baby-making days may be numbered.

SAN FRANCISCO -- A 13-year-old patient once came to Dr. Robert Cowan with an unusual request: She wanted to go to an amusement park and she needed him to talk her mother into it.

The mother assumed Cowan, a neurologist treating the girl for severe migraines, would take her side. Surely a day in the sun, riding roller coasters and sprinting around the park, would trigger a terrible headache.

"And I said of course she should go," Cowan said recently with a laugh. "And she went, and she got a headache, and she said it was totally worth it."

Cowan, director of Stanford University's new headache clinic, could relate to the girl. He has suffered migraines his whole life. Just two years ago, he risked a major headache to see an Eric Clapton concert. He understands all too well the choices "migraineurs" -- the word migraine sufferers often use to describe themselves -- have to make to live as normal and productive lives as possible.

SAN FRANCISCO -- Jeanne Nollman was a later bloomer.

She waited and waited for puberty to hit, and when she was 17 and still nothing had happened, she got tested -- and found out she had a rare condition called Swyer syndrome and would need supplemental hormones.

What no one told her until eight years later, when she demanded more information about her condition, was that she had the male X-Y chromosome pattern.

"That was typical back then, in the '70s," said Nollman, now 51 and living in San Leandro, Calif., with her husband and two adopted teenage children. "I guess they thought I might go jump off a roof and commit suicide with this information. But I must be an odd duck because I was just relieved."

Now she's trying to help other children -- and their parents -- learn about and even embrace their "disorder of sex differentiation," or DSD. It's the medical term for hermaphrodite, a word no longer used by doctors and patients.