All-boys Archbishop Riordan Catholic High School in San Francisco going coed, upsetting many parents, students

SAN FRANCISCO (KGO) -- Parents and students of Archbishop Riordan all-boys Catholic high school are feeling blindsided after the school's decision to start accepting girls in the fall. The decision happened Thursday, ending the school's 70-year reign as a single-gender learning establishment.

"It's sad. I'm hurt. My feelings are definitely hurt," said Ricardo Hernandez, a Riordan senior.

He says he has nothing against girls, but feels as though it took him four years at the school to realize the meaning of "brotherhood" and that the decision came suddenly just weeks after the nearby all-girls Mercy Catholic high school closes because of low tuition and lack of endowment.

"It's an uproar! All of a sudden it becomes a coed school they didn't have time to make the transition," says Ricardo's mother who is glad her son is graduating soon.

Principal Tim Reardon was adamant the school kept families in the loop since the news of the Mercy closure happened.

"Given the time frame we have because admission season is coming, I think we've done basically everything we possible can do to keep them involved," he said.

RELATED: Mercy High School, one of the last San Francisco all-girls Catholic schools, to close in June

Parents provided ABC7 News with a survey sent out by the school 10 days ago asking families to weigh in on the implications for Riordan with Mercy closing. Parents such as Deidre Von Rock say they never saw the results of the survey-and now feel duped.

"Our children are here because we all believe in the single gender education model. That's what we all pay for and what our contracts are for."

Many hypothesize the sudden absorption of girls from Mercy as a way to combat declining admissions. It's one of the reasons Mercy itself is shutting down. Riordan currently has 670 students while the school can fit up to more than a thousand. So far, 170 girls from Mercy have applied for the next school year.

ABC7 News asked one parent who declined to be identified if he will be sending his freshman son back to Riordan in the fall. He said he would have to weigh the options with his wife.

"We're not sure at this time," he said.

A Change.org petition to reverse the decision to make the school co-ed currently has more than 500-signatures.

According to the National Catholic Educational Association, since 2009 the number of students at Catholic Schools has declined by 18.4% across the country.