In a huge win for California children and families, this year Sacramento elected leaders decided to include funding in the state budget to protect Medi-Cal coverage for our state’s babies, toddlers and youngest children, helping to eliminate bureaucratic hurdles that would otherwise cause 1.2 million children to lose their access to health coverage.

But there’s a catch: If voters approve Proposition 35 this November, funding for continuous Medi-Cal coverage for children up to age 5 — and several other health care-related programs —  goes away.

As a mom of a 3-year-old, like many parents and caregivers, I know firsthand how critical the first years of a child’s life are. Ninety percent of brain development occurs in the first five years of life. This is the time when conditions like asthma, hearing loss and autism can be addressed and intervened early, giving a child the best possible odds to thrive.

Rolling back funding for a policy that ensures young children from low-income families can get the care they need to put them on a path toward a healthy life could prove devastating. Voters should vote “no” on Prop 35.

This setback is only one example of the harm to Californians that would result from Proposition 35.

I agree with the intention of Proposition 35. There is no question that Medi-Cal payment rates are too low, creating a barrier to access to care. The children and families we represent wait months for basic doctor’s appointments and often miss out on seeing specialists entirely.

However, while intended to increase Medi-Cal access, Proposition 35 actually jeopardizes billions of dollars in health care funding meant to support the Medi-Cal program.

Proponents claim that Proposition 35 simply extends and makes permanent an existing tax on health plans, something my organization supports. However, the measure places a very low cap on the tax rate for commercial health plans — one one-hundredth of the current tax rate on Medi-Cal health plans.

This structure is inconsistent with federal direction and risks California forgoing billions of dollars in revenue for the Medi-Cal program in the future. Medi-Cal is the primary source of health insurance for over half of California’s children, with 75 percent of those kids being children of color. We cannot afford to lose a single dollar that could be invested in supporting our children.

Moreover, the measure directs the funds the tax does raise to a select group of health care providers to the exclusion of a wide range of important services that our children and families need. For example, passage of Prop 35 would eliminate funding for fair wages for community health workers, the trusted messengers and key advocates for our communities, alongside other services for children with complex medical needs, seniors and people with disabilities.

There is another way. Through the legislative process and in consultation with patients, consumer advocates and Medi-Cal providers, California lawmakers enacted a balanced solution this year that includes increased payment rates for Medi-Cal providers, but also ensures health care access for our youngest children. Despite a state budget deficit, lawmakers avoided cutting Medi-Cal benefits that previously have been eliminated, like dental services. And lawmakers maintained California’s commitment to our immigrant communities by maintaining the expansion of Medi-Cal eligibility to all regardless of immigration status or age.

Proposition 35, on the other hand, would blow a $12 billion hole in the state budget over the next 2.5 years according to the state Department of Finance. While the pay raises for the providers included in Proposition 35 would be protected by law, many other programs and services that our children and families depend on would be at risk. We know that it takes more than a doctor’s appointment to keep a child healthy. Quality child care, safe housing, healthy food — these are all areas that need more investment, not less, but Proposition 35 would tie the state’s hands in making budget decisions and fully funding what communities need.

This year’s state budget makes important strides to improve health care for kids and families. Let’s ensure this is not undone by a narrowly focused ballot measure.

Alvarez is president of The Children’s Partnership, a nonprofit advocacy organization working to advance child health equity by ensuring all children have the resources and opportunities they need to grow up healthy and thrive. She lives in San Diego.