When Emilyn Heng found out that her second son was deaf, just like her first, she was sad. But not for long.

"I was sad for half a day but life has to move on," she says.

A practical soul, she started planning for her sons' future.

She decided she would slog and open a provision shop or petrol kiosk for them to run in case they were held back by disability or did not do well at school.

But at the same time, she resolved to do everything she could to make sure they were not disadvantaged.

She read up on deafness, enrolled in correspondence courses that taught how to bring up hearing-impaired children, sent her boys to speech therapy and helped them with their studies.

"I was very tough on my kids; I was worse than a Tiger Mum," says the 54-year-old who helps her husband run a contracting business. Tiger mothers are so called for their fierce emphasis on discipline and achievement.

Her tenacity paid off beyond her expectations.

Elder son Lionel, now 31, became a defence scholar and went on to obtain double degrees in science and economics at Carnegie- Mellon University in the US and a master degree in science from Stanford. Now a computer scientist with the Defence Science and Technology Agency, he will soon be graduating with his doctorate from ETH Zurich, one of the world's leading universities for technology and the natural sciences.

Younger son Joseph, 28, is no less accomplished. He has a bio-engineering degree from Johns Hopkins University and has just completed his medical degree at Yale, both in the US.

The brothers say they owe their mother a lot.

Lionel, who is married to a teacher and has two children, says: "She taught us that life is not a bed of roses and that we have to work hard for what we want. She said that even for able people, some eventually stumble at some point in their lives because they expect much in return for little work."

Candid and buoyant, Mrs Heng has always been a hardworking go-getter.

She was born the sixth of seven children to illiterate parents who came to Singapore from Fujian in China. The family lived in a kampung in Changi.

"My father died when I was about four years old. He was a pig trader, and a simpleton who often got swindled. And he had a drinking problem too," she says.

Life became harder after he died. The family continued rearing pigs and chickens to make ends meet.

"I remember having a little piglet as a pet. I'd feed it every day but I came home after school one day to find that it had been sold," she recalls.

To make ends meet, her mother also became a washerwoman to the many expatriate families living in the area.

"I remember her palms were always wrinkled and full of calluses. I knew she often had to borrow money so I would always save my school allowance and give it back to her," she says.

Pint-sized but ebullient and confident, she was popular at Changkat Changi Primary School and Sennet Road Secondary. "I had a lot of friends and even the bigger girls would listen to me."

After completing her O levels, she learnt how to type and landed a job as a clerk at Changi Sailing Club.

Not one to rest on her laurels, she was always taking courses to better her prospects. Besides getting her London Chamber of Commerce and Industry accounting certificate, she also took courses in materials handling.

Her resourcefulness led to a job as a purchasing clerk in an aviation company where she eventually worked her way up to become its purchasing officer.

At 19, she helped her then-boyfriend and now husband Patrick Heng to set up a contracting business servicing the oil refinery industry. For nearly a decade, she helped to run the business while holding down a full-time job.

Patrick Heng Contractor did well.

"We started doing jobs worth $300, then $500, then $10,000 and then even $1 million," says Mrs Heng who still handles payroll and other administrative matters for the company which now has an annual turnover of more than $7 million.

All went well and she was 24 when she married Patrick.

The following year, Lionel was born. "He was a very intelligent baby. At eight months, he could assemble a 50-piece jigsaw puzzle of The Smurfs," she says, referring to the fictional colony of small blue creatures created by Belgian comics artist Peyo. "We were so happy, we thought we had a genius son."

But compared to some of her friends' children who were mouthing words like "Mama" and "Papa" before they turned one, Lionel was rather quiet.

Suspecting that something was wrong with his hearing, she took him to the Ear, Nose and Throat department of a hospital. Many tests later, 14-month-old Lionel was diagnosed as hearing-impaired.

Mrs Heng's world came crashing down.

"For two months, I couldn't work," she says, starting to tear at the memory. "But I snapped out of my depression because I told myself I had to do something for him."

Determined to find out as much as she could about the disability, she joined the Singapore Association For the Deaf and attended support groups for parents of hearing- impaired children.

She travelled to the John Tracy Clinic in Los Angeles and the Taralye in Melbourne, both known for helping children with hearing loss.

"I learnt very practical day-to- day skills on how to deal with deaf children, like how to potty-train them. I also took many correspondence courses."

Meanwhile, she went through the heartbreak of several miscarriages. "I wanted a second kid. It was easy for me to conceive but difficult for me to carry the baby to term."

Joseph came along three years after Lionel, in 1986.

"When he was born, I felt that he too was different. I was sharing a room with another new mother in the maternity ward. When she went to the toilet, I'd clap my hands. My baby did not cry; hers yelled," she recalls.

She kept her fears to herself but subsequent tests showed that her second baby was deaf too. Around that time, she was retrenched from her job at the aviation company.

Mrs Heng decided to devote all her energies to raising Lionel and Joseph. Besides enrolling them at the Canossian School For The Deaf, she also paid $7,000 each month for them to attend speech training at Dover Court Preparatory School. She sat in on all the sessions, made friends with the speech therapists and repeated the drills at home with her sons.

"I'm lucky that we had the means to do it," says Mrs Heng, who made shrewd property investments with her husband. The couple also adopted a daughter, Janice, now 24.

Without batting an eyelid, she admits to being very tough.

The boys had to read aloud every night; they had to speak instead of relying on sign language and had to wear hearing aids even though they loathed doing so.

"The cane may take care of things temporarily but in the long run will give you more problems so you just have to explain what is good for them. They were very good children, we did a lot of bonding during these sessions," she says.

Joseph, who like his brother had a cochlear implant during his teens, says: "When we were growing up, she devoted a tremendous amount of time at home teaching and reading to us and making sure we didn't fall behind in school. If we had deficits in our education because of difficulties coping at school, she would look for those deficits, read up on them and then help us to make up for the shortfall."

Her efforts paid off. Both boys went from Canossian to St Anthony's Primary and then St Joseph's Institution (SJI).

At SJI, the brothers were high achievers. Both scored seven A1s and one A2 for their O levels, and went on to complete their pre-university education at National Junior College. Joseph is also an accomplished pianist and has a Grade 8 in piano.

Mrs Heng says she has always taught her two sons to break their own barriers.

"They have to do it so that they won't be disappointed. Their wants are not always met. When they were at school, they were told they could not join the National Cadet Corps or St John's Ambulance Brigade or become scouts," she says.

The boys heeded her advice. When Joseph could not get into medical school at the National University of Singapore, he applied to Johns Hopkins, did a degree in bio-engineering and qualified for medical school at Yale. Recently married, he is now doing a one-year programme in oncological research at the same university.

He says: "Despite the difficulties we faced growing up because of our hearing impairment, she would always tell us to persevere and ignore people who told us that we 'can't do it'."

Mrs Heng says proudly: "People say the deaf cannot learn Mandarin, cannot learn music, cannot go to medical school. Joseph is proof that they can.

"I'm happy my boys cleared the way for others who are hearing-impaired."