A New York City university professor had admitted using bathrooms at Target and Starbucks stores for sexual activities to help women get pregnant.

Ari Nagel, 40, who works at Kingsborough Community College, which is part of the City University of New York (CUNY), said he provides seminal fluid to women who want babies.

Just last week, he said he did it at the men's bathroom in a Target store on Atlantic Avenue in Brooklyn, according to the New York Post.

The report said Nagel became a sperm donor to dozens of women and has sired 22 kids in the last 12 years with 18 women.

His clients include lesbian couples and single women who want to have babies but do not want to spend money at a sperm bank.

"This isn't time-consuming, and I'm doing it anyway. It's very easy for me to do," he said of his activity.

The oldest among the kids he sired is a 12-year-old.

He uses the public bathrooms at Target and Starbucks to procure samples and give them to women.

"You don't want to do it in one where people are knocking," he said.

The American Family Association (AFA) has gathered almost 750,000 signatures calling for a boycott of Target following its decision to allow transgenders to use the store's bathrooms according to their gender identity.

Nagel said he first conducted his sperm donation eight years ago with a friend.

"I actually tried to fix her up. I had a friend who I thought would be a better match as a sperm donor," he said. "He got cold feet at the last minute."

It ended up with Nagel going with the women to a fertility clinic.

Nagel is proud of what he is doing for women.

"I just love seeing how happy the moms and kids are . . . That's why I do this," he said. "It's the gift that keeps on giving."