Twins. One in 30 babies born is a twin – an increase of 76 percent since the 1980s according to the National Center for Health Studies. With this increase, having twins who play the same sports is becoming more and more common.

Being twins on the same sports team can affect performance, relationship and the team dynamic.

Junior Jackie Mundis, who is on the curling and ultimate frisbee teams with her sister, Allie, said that being a twin affects her performance positively.

“We work really well together on the field or on the ice,” Jackie Mundis said. “Sometimes, when one of us does something good, it reflects on both of our performances.”

According to sophomores Katherine and Erin O’Brien, being twins on the same soccer and track teams does entail some stress.

“We’re so compared to each other, it makes it harder for one person to do less than the other,” Katherine O’Brien said. “We always want to be better.”

On the other hand, senior Andrew Gilbert, who plays soccer, lacrosse and baseball with his twin brother Jay, said that there is no stress, just extra competition, which can be a good thing.

“He motivates me to work harder and if he makes varsity and I make JV, there might be a little more competition,” Gilbert said. “I think it is motivating to have someone who is looked at as your equal.”

According to Allie Mundis, she and Jackie are at the same level with their sports due to the fact that, as twins, they spend a lot of time with each other.

“We used to play basketball, and we would have the same record,” Allie Mundis said. “We are pretty even, since when we have extra time, we practice together.”

Katherine and Erin O’Brien said that coaches and teammates sometimes treat them as a unit rather than individuals by calling them “twins” or “O’Briens.”

“It gets annoying, but what can you do? You get used to it,” Katherine O’Brien said.

This is also true for the Mundis twins, who were hard to tell apart when they were running.

“Everyone would be confused,” Jackie Mundis said. “Our coach never knew which one we were, so it is kind of a joke on the team.”

According to Gilbert, he and his brother get more frustrated with each other than they would with another teammate when one of them makes a bad pass or messes up in a set. However, Gilbert thinks that playing the same sport helps build his and his brother’s relationship.

“It’s fun to have someone to help break down what happened in the day,” Gilbert said. “I think it helps our relationship because we have something in common that we both love to do.”

Erin and Katherine O’Brien each play a sport without the other, but find that it is not that different from playing on a team together.

“Last year, I played lacrosse, and she did spring track, to see how it would work,” Erin O’Brien said. “It was fine. It didn’t feel that different.”

However, Allie Mundis sees a stark contrast when she is not with Jackie. She said that when they are together they joke around more, so the team becomes more easy going.

“When I was on a school trip last year, I missed a whole week of the season, and Jackie said that it was really different,” Allie Mundis said. “It was more serious. When we are together, it’s a lot more fun.”