Double trouble rising?

Twins. Seems like they’re the celebrity accessory of choice these days.

Brad Pitt and Angelina Jolie reportedly have been offered millions for the first photos of newborns Knox and Vivienne, born a week ago in France.

Jennifer Lopez and Julia Roberts, Sean “Diddy” Combs and Dennis Quaid each have a set of twins. Is it something in the water?

If it seems like twins are turning up more frequently, it’s because they are.

Dr. R. Stan Williams is an infertility specialist at Shands at the University of Florida.

Multiple births are becoming more common, Williams said, due in part to the advancing age of mothers and the development of techniques to assist couples who have difficulty conceiving, such as in vitro fertilization.

Women in their 30s and 40s have higher levels of the hormone estrogen, so their ovaries are stimulated to produce more than one egg at a time. When fertility drugs are used to stimulate the ovaries, several eggs at a time are often released.

Your chances of conceiving twins can even vary with the type of fertility drug you are taking, Williams noted. And although few celebrities are talking about it, he suspects fertility treatments played a role in many of the recent high-profile twin conceptions.

The older you are, the greater the chance of having fraternal twins. The twinning rate is doubled for women ages 35 to 40, then drops. According to the latest statistics, you are less likely to give birth over the age of 45, but if you do, there is a 33 percent chance that it will be a multiple birth.

Other factors can affect your likelihood of producing twins, including whether you’ve had an earlier pregnancy, or whether fraternal twins run in your family. African-American women have the highest incidence of twins; Asian women have the lowest.

Gainesville residents Jonas and Traci Graham are parents to three teenagers — Meg, 16, Brittany, 17, and Clay, 18. Two years ago, on Father’s Day, Traci gave birth to twin boys, Jake and Gavin.

Traci was vacationing in California this week with the twins while her husband wrestled with the task of opening a new restaurant, J. Coconuts Beach Grill in High Springs.

Traci serves as president of the Gainesville Area Parents of Twins Club.

She had no advice on raising a twosome for J-Lo or Brangelina. “They’ve probably got two nannies for each child,” she offered.

“But for us normal people, I’d say as soon as you find out you are going to have twins, get as prepared as possible,” she said. “We had a closet full of diapers and another full of clothes ranging up to size 14 before the boys arrived.”

Traci said people often tell her, “Thank God it’s you and not me.”

“I have to agree with them because this is what I’ve always wanted,” she added. “Call it the power of positive thinking, but three months before I got pregnant, I told my husband we were going to have twins on June 18. And we did just that.”

Tim and Cindy Martin of Gainesville have two sets of fraternal twins, 7-year-olds Mark and Holden, and David and Brian, who just turned 2.

Cindy said the first year with twins is a real roller-coaster ride.

“When you have not one, but two children who can’t do anything for themselves, that can be a real challenge,” she said. “Some people with kids that are 13 months apart say it’s almost like having twins. Believe me, it’s not!”

Now the Martins are facing the “Terrible Twos” with David and Brian.

“I almost felt this past year was worst than the first,” Cindy said. “It seems that with twins, any stage they’re in is just compounded.”

Traci Graham said in at least one respect, having two babies at once is easier than what she calls “a singleton.” The twins entertain each other.

She describes listening to the boys on the baby monitor in the mornings.

“They have their own language,” she insists. “They’ll each say something in this strange language and just crack each other up.”

Around two in every three sets of twins are fraternal, where two separate eggs are fertilized by two separate sperm. Fraternal twins are no more alike than two siblings born at separate times.

Identical twins occur in one in three sets, when a fertilized egg divides into two while it is still a tiny collection of cells. Each half grows into a baby, and each has the same genetic information.

About four births in every thousand are identical twins, while the rate of fraternal twins varies more widely. Worldwide, fraternals represent approximately 22.8 per thousand births. Twins account for more than 90 percent of multiple births.

The most fraternal twins are conceived in July, the fewest in January. The odds of having two sets of identical twins are at least one in 70,000.

Earlier this month, a 70-year-old woman in India became the world’s oldest new mother after giving birth to twins. Her 77-year-old husband mortgaged his land to pay for invitro fertilization treatment. The couple have two grown daughters and five grandchildren.

“At last we have a son and heir,” Charan Singh Panwar told a British newspaper.

Diane Chun can be reached at 374-5041 or by e-mail at chund@gvillesun.com.