The topic of today’s lesson at Glen Park Elementary in California: Life isn’t fair.

An unidentified San Francisco public school teacher is being forced to pay for her own substitute teacher while on medical leave. The second-grade teacher is absent while receiving treatments for breast cancer — and parents are outraged.

"She's an incredible teacher and that's not fair. That’s crazy!” Glen Park parent Elia Hernandez told ABC7.

Parent Abby Hipps added, "She's wonderful, she's a beautiful lovely great teacher. She's one of the best teachers. It's terrible."

So why exactly is the educator in this position? Because of a1970s California education code, public school employees on extended sick leave will have the pay of their replacement deducted from their own paycheck— however the state law leaves it up to the individual cities or districts to implement their own regulations.

San Francisco Unified School District’s policy allows teachers to accumulate 10 paid sick days per year. Once those days are exhausted, they may be eligible for up to 100 extended sick leave days. However, for the duration of the extended sick leave, $195 will be taken out daily from their salary to pay their substitute, NBC Bay Area reports.

“This reflects California Education Code language related to extended sick leave that applies to all other school districts in California,” Laura Dudnick, a spokesperson for SFUSD, tells Yahoo Lifestyle. “This is not unique to San Francisco. This is not a district-only rule.”

That means, the teacher, who wishes to remain anonymous to protect her privacy, will only receive partial pay at a time when many San Francisco teachers are struggling to even make ends meet in a city with the second highest cost of living in the country. (The cost of living in San Francisco is 96.3 percent above the U.S. average, with the average home price at a staggering $1.2 million.)

"I just can't believe how grossly unfair it is," parent Amanda Kahn Fried told KQED. Fried has two children enrolled at Glen Park School and noted that “parents were outraged and incredulous” upon hearing the news. "Can you imagine telling doctors they have to pay for their replacements? It just doesn't make sense. That's not the employee's responsibility — that's the employer's responsibility."

Story continues

Glen Park parents have raised more than $13,000 to help the instructor pay for her replacement as she receives treatment (the GoFundMe page has since been disabled because the extra attention was causing the instructor undue stress). According to NBC Bay Area, it will be just enough to cover a substitute teacher through the end of the school year.

The only alternative option for the unidentified teacher is the sick bank pool, a program that allows public school employees to donate unused sick days to fellow teachers after they’ve exhausted even their extended sick days. However, when the Glen Park teacher’s colleagues tried to donate days to her, she realized she had never joined the program that only allows entry during specific periods.

“Officially, we have nothing in the contract beyond that,” Susan Solomon, the head of the San Francisco teachers’ union, told the San Francisco Chronicle. “I think we could always do better. In a broader sense, I think single-payer health care is the answer.”

Fellow Glen Park School teachers are taking their colleague’s misfortune to heart. “It makes me worry if that were to happen to me,” Glen Park School teacher Brenda tells ABC7. “I have to plan accordingly and that's not fair you know."

Read more from Yahoo Lifestyle:

• Two 'Teacher of the Year' recipients skipped the White House ceremony: 'Speak up if you don’t agree with something'

• Teachers reject Betsy DeVos' appreciation video: 'Thank me by resigning'

• Former teacher shares powerful resignation letter: ‘I won’t be in an abusive relationship with public education’

Follow us on Instagram, Facebook, and Twitter for nonstop inspiration delivered fresh to your feed, every day.