As is customary in China, Zhang Yongfei and Tian Xiao held a family celebration this month to mark the 100th day since the birth of their son. Unlike most new parents, however, Zhang will never see his child, and Tian will never hold him.

"You are my eyes, and I am your hands and legs," Zhang, 32, who was born blind, told his wife at the party in Taiyuan, Shanxi province.

Tian, 27, has Lou Gehrig's disease－also known as amyotrophic lateral sclerosis, or ALS－which is a progressive condition that attacks the nerve cells that control muscles. Over time, it leaves patients struggling to walk, speak, swallow, and even breathe. So far, there is no cure.

For the past few years, Tian has been paralyzed except for some movement in her right hand. Yet in May, she became only the second woman with the disease to successfully deliver a child in China.

"Were it not for doctor Zhang Yanli, I would not have become a mom," she said.

Zhang Yanli, an obstetrician in her late 50s from the No 1 Hospital of Shanxi Medical University, first met Tian when she was three months' pregnant in November.

She warned of the dangers of going ahead with the pregnancy, but Tian was resolute. "I told her that I was placing two lives into her hands: my baby's and my own," she said. "I knew that this was coming, and it was not something that could be driven away. It was probably my maternal instinct."

Zhang Yanli, who has 38 years of experience, later told the media that it was a difficult decision to become Tian's doctor. "I was shocked after learning about her condition and her dream," she was quoted as saying.

But the obstetrician was moved by Tian's determination and courage. She studied her new patient's medical records, going back more than 20 years, and researched many academic documents.

She found out that the only recorded case of a successful C-section carried out on a woman with Lou Gehrig's disease in China was in 2013.

Zhang designed a tailor-made prenatal care schedule for Tian, and closely monitored mother and baby's physical condition throughout the pregnancy. She also held group consultations with experts in anesthesiology, neurology, neurosurgery and cardiovascular medicine to assess the risks and prepare for the delivery.

The hard work paid off. Tian gave birth to a healthy baby boy weighing 2.9 kilograms on the morning of May 3. His parents have nicknamed him "Miduo", which means "lots of rice", in the hope he has a plentiful life.

Having a son has brought the family happiness, hope and an important challenge, according to Zhang Yongfei. He said the couple will do their best to create a good environment for Miduo.

After graduating from a nursing school for the visually impaired, Zhang Yongfei opened his own massage clinic, employing six people.

Tian began studying graphic design at age 16 and opened her own recording and animation studio in 2010, before she lost the ability to move. Now, she works by controlling a computer with just the little finger on her right hand.

"Although it takes me half an hour to finish an operation that a healthy person could do in five minutes, I'm happy that I'm self-reliant. I like my work," she said.