It was clear from an early age their baby Johnny would never walk nor talk.
Trying to come to terms with the experience, the young couple moved away from their home in Glasgow to build a new life in Cardross, near Helensburgh, Argyll and Bute.
As the years passed they met others in a similar situation and, on the family's return to Glasgow, Mrs Shapter and nine other parents took the support they received from each one step further by setting up a charity dedicated to helping children with disabilities and their families.
On Wednesday that charity, now called Enable Scotland, marked its diamond anniversary.
About 70 people, including long-standing and new members of the charity, celebrated the 60th birthday at the ABode Arthouse Hotel, Bath Street, Glasgow, after Mrs Shapter and her friends advertised a public meeting.
In the 1950s the building was the education offices for Glasgow Corporation and it was there on April 9, 1954 that 300 people gathered for the founding meeting of the charity, originally called the Scottish Association For The Parents Of Mentally Handicapped Children.
Johnny died, aged 28, in 1973, and Mr and Mrs Shapter died in 2002 and 2011 at the age of 86 and 91 respectively. Toward the end of her life Mrs Shapter wrote a book about her experiences, called Johnny.
Among those who attended the party was Jacqueline Keenan, 55, Johnny's younger sister, who helped cut the charity's birthday cake with Anne Trail, daughter of Jim Henderson, another founding member. A plaque marking the founding of the charity was also unveiled.
Mrs Keenan, who has three children, said she was extremely proud of her mother for her role in setting up the charity. It has grown steadily over the years, and now has 4500 members and operates across 44 branches in Scotland.
"I think she and my father felt terribly isolated when Johnny was born," she said.
"They had no indication during the pregnancy that anything was wrong. It must have been a difficult time. But she was a very determined woman and wanted to use her experience to help others."
The problems Johnny and his parents encountered in the 1940s and 1950s were considerable.
There was a huge social stigma attached to having a child with a disability and parents often hid themselves and their child away.
There were also few services and parents were often left to cope on their own. The children also faced huge disadvantages and discrimination. They were branded "uneducable", hidden away in long-stay institutions, had no right to go to school and no option as they got older to live independently, have a relationship or a job.
Today, people with learning disabilities still face discrimination and challenges. Many report experiences of bullying and most find it harder to get a job and form a long term relationship than those of the general population. People with learning disabilities also have more health problems and are likely to die 20 years earlier than the general population.
However, compared to the situation in 1954, their lives have considerably improved - thanks in large part to the campaigning carried out by charities such as Enable Scotland.
Peter Scott, chief executive of Enable Scotland, said: "Thousands of people who have learning disabilities no longer spend their lives hidden away in institutions, excluded from their communities. Many live independent lives, have their own home, paid employment, meaningful relationships, and play an important role in their communities. Many people who have learning disabilities no longer need others to speak on their behalf."
Two such people who have overcome the challenges faced by people with learning disabilities were among those at Wednesday's party.
Tara McKay, 22, from Edinburgh, a young ambassador for the charity, said her disability has not stopped her from enjoying a full and active life.
"I love my job. I work with children in a nursery. In the future I might like to work with children who have to stay in hospital. I am engaged to Tony, my dream is a dream wedding in 2016!"
Donald Stirling, 59, from Inverness, who was awarded the MBE in 2009 for his services to people with learning disabilities, spent 14 years at Craig Phadrig long-stay hospital in Inverness, after being admitted at the age of 15. He was discharged when he was 29 and later found a job and got married.
"Enable Scotland has changed my life completely and allowed me to achieve things I would have never thought possible," he said.
"The important thing it did was to make me believe in myself and give me confidence. These were the tools that allowed me to speak out, make myself heard and take control of my life. Now nothing will stop me living my life how I choose."