Rich Pedroncelli/AP Debbie Ziegler holds a photo of her daughter, Brittany Maynard, and get a hug after the California legislature approved the End of Life Option Act last year.

California's new right-to-die law went into effect Thursday, allowing terminally ill patients to choose to end their own lives.

"Simply having the option of medical aid in dying and the ability to shorten an unbearable dying process provides great peace of mind to terminally ill people and to their families," Stanford Medicine physician Catherine Sonquist Forest told reporters Wednesday.

Under the End of Life Option Act, which passed last year, terminally ill patients with a prognosis of six months or less to live can obtain a prescription for a lethal dose of medication.

The law provides several protections against abuse. It requires two doctors to sign off on the patient's prognosis and mandates that the patient make a written request and two oral requests for the lethal medication at least 15 days apart. Patients must also be deemed mentally competent and capable of making decisions about their own health.

Individual doctors and hospitals can choose whether or not to offer patients this option. Many large health care systems in California -- including Kaiser, Sutter Health, the University of California and Stanford Medicine -- have said they will allow their patients to seek aid in dying, according to Compassion & Choices, a leading nonprofit in the "death with dignity" movement. One doctor in Berkeley has opened a new practice specifically for seriously ill patients who seek guidance in ending their own lives.

Some religiously affiliated hospitals, however, are likely to opt out of the program.

The law was inspired by Brittany Maynard, a 29-year-old California resident who was diagnosed with terminal brain cancer. Maynard made national news for her decision to move to Oregon and seek care under that state's right-to-die law.

“I am heartbroken that I had to leave behind my home, my community and my friends in California. But I am dying and I refuse to lose my dignity. I refuse to subject myself and my family to purposeless, prolonged pain and suffering at the hands of an incurable disease," Maynard said in a video message to lawmakers prior to her death in late 2014. "No one should have to leave their home and community for peace of mind, to escape suffering and to plan for a gentle death.”

In a conference call with reporters on Wednesday, Maynard's widower, Dan Diaz, explained why the issue was so important to his late wife. Diaz and Maynard's mother, Debbie Ziegler, have become two of the death-with-dignity movement's most vocal advocates, testifying in front of the California state legislature last year and aiding similar campaigns in other states.

Having the option to die on her own terms "allowed [Maynard] to focus on living life," said Diaz.

"She didn't have to be consumed with that fear of that brutal dying process that was coming for her," he said. "This program, its very existence empowers the individual and it provides a great sense of control and relief."

On the same call, Elizabeth Wallner, a single mother who has battled advanced colon cancer since 2011, said that she's relieved the law is going into effect and that she takes comfort in knowing she can end her life if her "suffering becomes intolerable."

"I don't want to die, but death itself doesn't really scare me," Wallner said. "What scares me the most is dying slowly and painfully, and traumatizing my beloved son Nathaniel, my parents and siblings, and the other people in my life whom I love."

While it's not known how many Californians will take advantage of the new law, statistics from Oregon offer some perspective. Since the latter state's right-to-die law went into effect in 1998, the number of prescriptions and related deaths has increased steadily. In the first year, 24 people received prescriptions for lethal medications, while 16 patients eventually took the medicine and died. Last year, 218 patients were prescribed such medications, and 132 decided to take them. In total, 991 terminally ill Oregonians have chosen to end their lives thus.

Access to the new option is an issue. While Californians in major cities are likely to find a doctor who will aid them in dying, residents of less populated areas may not have the same resources available. Compassion & Choices' California director, Matt Whitaker, said that access is "absolutely a concern" and that his group is working to educate patients and physicians around the state about the new measure in hopes of increasing the number of participating facilities.

The law has been met with criticism from Catholic groups objecting on religious grounds. Others have raised the possibility of lethal drugs being offered to poor patients as an alternative to expensive, potentially life-saving treatments. A UCLA study released in May, which was based on data from Oregon and Washington state, found those fears to be unsubstantiated. It said that most patients who sought aid in dying were white, highly educated and privately insured.