THE PARENTS: Lou Gana, 36, and Gina Gana, 35, of Drexel Hill

THE KIDS: Harper Christine and Hailey Marie, born October 13, 2016

HOW THEY TELL THE KIDS APART (ASIDE FROM THE DIFFERENTLY DECORATED HELMETS): Harper has a longer face, and Hailey's face is more round.

It felt, Lou says, a bit like scheduling a tonsillectomy: At 11:30 a.m. on Oct. 13, they would become parents. With a planned C-section at Lankenau Medical Center, there would be no water breaking at midnight, no predawn dash to the hospital, no 22-hour labor.

Instead, there was a nurse asking Lou, "Dad, are you ready?" after Gina was prepped for surgery. "I scurried back; I didn't look at anything but the floor, because I didn't want to pass out. I sat next to Gina's head."

The doctor said, "Here comes Baby A." Two minutes later, he pulled out Baby B. And in a second, Lou says, "We went from having minor responsibilities to two humans we now had to take care of."

They'd already named their daughters: Harper (Baby A) and Hailey (Baby B), a gesture of anxiety and faith when the two were still in utero and the OB warned about the possibility of twin-to-twin transfusion syndrome, when one baby robs the other of blood and nutrients.

There were no remedies to prevent that from happening. "That was the scary part, the heartbreaking part: These are our children, and there's absolutely nothing we can do for them," Lou recalls. "We looked at the worst-case scenario and decided, 'Let's name them now.' "

The couple knew early on — if not during that first date at North Bowl in Northern Liberties, then shortly afterward — that they wanted children. They'd met by happenstance, when Gina moved in with her parents next door to where Lou was living with a friend.

They chatted at a block party, then traded text messages. Both, it turned out, had large, tight-knit families and eclectic musical tastes, ranging from Hall & Oates (they've seen the duo five times) to rapper Jay Z.

The first "official" date happened in October 2011; two years later, the night before Thanksgiving, Lou proposed, with champagne, flowers, and a party — a surprise to Gina — with the relatives and friends who would later be attendants at their wedding.

On that day, between the ceremony and the reception, a photographer captured the pair dancing by themselves, just before 300 guests streamed into the room. Later, there would be hubbub — an aunt broke a foot on the dance floor and a longtime friend dislocated a hip while getting out of a chair; both had to be rushed to the hospital — but that photograph seized a moment of serene togetherness.

A year and a half later, serenity came to a crashing halt. At Gina's first ultrasound appointment, the OB swooshed the probe over her still-flat belly and murmured, "Oh, that's interesting."

"What, I'm not pregnant?" Gina said.

"No … it looks like there's two."

Lou remembers a sudden sweat, a queasy ripple. "You've got to be bleeping kidding," he managed to say.

"I just cried the rest of the day," Gina recalls. "I was shocked, excited, and worried about money." But the pregnancy was relatively smooth: not a moment of morning sickness, and after the danger period for twin-to-twin transfusion syndrome had passed, they were able to relax a bit.

During multiple trips to Babies R Us for doubles of everything — strollers, cribs, car seats — they inevitably learned that some other customer, or the sales clerk, was a twin, knew a twin, or had twins in their families. "You'll do fine," people assured. "They'll always have someone to play with … they'll be best friends."

Still, nothing prepared the couple for that first night at home, when both babies cried inconsolably from evening until morning. Gina and Lou, in tears themselves, were about to whisk them back to the hospital when the girls finally fell asleep in their car seats at 6 a.m.

At an early visit, their pediatrician diagnosed congenital torticollis — shortened neck muscles caused by the way the babies had been bunched together in the womb — and recommended physical therapy to correct the problem. It was the therapist who noticed that the girls' constant head-tilt was causing plagiocephaly, flattened spots on their still-soft skulls.

The remedy was a pair of cranial orthotic helmets, $1,800 each, that the girls wear 23 hours a day. The prescription came with its share of distress — the girls cried when they first wore them; Lou and Gina fretted that they were hurting their daughters — but also brought a dose of perspective.

"There are other families with much bigger issues going on, like open-heart surgery on infants," Lou says. "We can fix my girls' heads." He's turned his gratitude — for a medical remedy and the resources to afford it — into a way of helping less-fortunate families who face the same concern.

Helmets 4 Hope, a nonprofit Lou started, will raise money through contributions and provide grants to families who can't afford treatment for plagiocephaly. It raised $1,000 in the first week the website went live.

In the meantime, Harper and Hailey have adjusted to their custom headgear, and their parents have learned to field strangers' questions. When a child at the mall ran over and said, "They're so cute! Why are they wearing those things?" Lou explained, "Their heads aren't as round as yours, so they wear helmets."

Gina looks forward to the day, a few months from now, when the girls won't need those helmets anymore; she envisions beach vacations, a trip to Disneyland, a first communion. Lou leaps ahead even further, picturing his daughters as teens, by his side at a Pearl Jam concert.

There are still so many unanswerable questions: Will Harper and Hailey share preferences and habits? Will they play basketball or try out for school plays? Will they tolerate their parents' taste in music?

But for now, one problem has a solution: "tummy time" at the end of each day, with all four of them parked on the carpet, Lou and Gina massaging their daughters' necks or bolstering them while they sit up. Their pit bull, Rocky, is lying nearby. The girls are giggling.