The Marxens are a basketball family.

One of the prized features of their Eastside home is the basketball half-court with a three-point line that blends seamlessly into the front driveway. Tom and Vicky were Sonics season-ticket holders before the team’s relocation in 2008 and regulars at Storm and University of Washington men’s and women’s games. And the couple’s four children all played varsity hoops for Eastlake.

Sometimes Tom and Vicky — who played tennis — wonder how they came to have four talented basketball players.

The youngest, Gina, a point guard, is the most gifted at the sport, leading Eastlake’s girls basketball team through a program-best 22-2 season and Class 4A state-tournament berth. The Wolves play Lake Stevens in a regional opener at 2 p.m. Saturday at Bellevue College.

She’s also adopted.

“My dad is really competitive and really driven, which probably led to all of us being very determined,” Gina said of Tom, a dentist. “But I’ve definitely always wondered about my biological parents and how much I am alike with them because I’ve read so many different sports-genes books about whether it’s nature versus nurture; how much is attributed to your environment and how you grew up. So, I’ve wondered if my (biological) family or parents are athletic or how much is attributed to my family now.”

It’s a question that will likely go unanswered. Tom and Vicky were part of a Bible-study group with longtime friends when one couple adopted a daughter from China. Inspired, five of the other couples, including the Marxens, also adopted daughters from the country through Faith International Adoption.

After an 11-month process, Tom and Vicky, a physician, returned from China with Gina. Vicky’s parents and three biological sons were at SeaTac International Airport to welcome their sister to the family, the boys each holding roses.

Instantly, Bibles, babies and basketball filled the Marxens’ lives. The friends — who’ve known each other for more than 20 years — raised the girls and blended families together. The daughters were even dedicated together at Westminster Chapel of Bellevue.

“It’s cool because we all come from a same area, but personality-wise, we’re all very different,” said Marxen of the girls who last were together for New Year’s in January. Gina couldn’t make a dinner for the Chinese New Year on Friday because of basketball practice.

“Sometimes I forget that I’m adopted because I’m so invested in my family and they’ve provided such a nurturing home,” Gina said. “It’s such a fun place to be around. But it’s definitely nice to have that group to fall back on whenever I am curious about where I came from. None of us really knows, and we’re able to be open and talk about it.”

As a toddler, Gina wanted to be like her brothers Chad, Lance, and Troy — a tale no different from most girls with older siblings who excel at sports. Chad, who was 8 when Gina was brought to America at age 1, had The Gun shooting machine and is the scorer. Lance is the wide-body post and Troy, the youngest boy, is a heady guard like Gina.

When they were in the gym practicing, she was on the sideline mimicking their moves. And when they were jumping rope or running sprints, she was there, too.

“We always noticed that she was a really observant little girl and picked things up quickly,” Vicky said. “It’s been very special to watch (basketball) blossom in her.”

By third grade, Gina showed enough potential for her parents to invest more in her basketball passion. She played for Seattle Transition and Tree of Hope’s traveling AAU teams and trained with former UW guard Gary Gardner.

Her maternal cousin, Alyssa Charlston, who led Idaho to the NCAA tournament in 2013 and 2014, also worked with Gina. An Eastlake alum, Charlston is a reason her cousin signed to play with the Vandals in the fall.

For the Wolves, Gina averaged 6.5 assists per game and shot 40.2 percent from three-point range during the regular season. Her pinpoint passes to sophomore post Keeli Burton were hard for opponents to defend, while senior guard Cameron Edward is an outside option for Marxen in the offense.

“When Gina decides to take over, we all get super-happy,” Eastlake coach Sara Goldie said of Marxen’s scoring abilities. “But she’s created a great team around her because of her willingness to set up other players in their most successful positions. She’s the most cerebral player I’ve ever coached, and I started coaching in 1998. I mean, she understands the game better than us sometimes.”

Gina’s a natural, no matter where it comes from. Where basketball will take her, she hopes, is first a deep run in the state tournament and then a successful career at Idaho. Maybe even a year playing overseas, but she’s more interested in entering the medical field as a career — another family trait.

“Having children at all is a great privilege and responsibility,” Vicky said. “We were able to have children, first of all, and then to be able to adopt and have this family the way that it is. … You have to open to the journey of your life because this has been a great blessing for all of us.”

Jayda Evans: 206-464-2067 or jevans@seattletimes.com. On Twitter @JaydaEvans