Mr Lee Hsien Yang was the son who chose not to follow his father's footsteps into politics.

He did things his way and carved a career in the corporate world.

Not that his parents did not try to influence his choices along the way.

When he was picking a graduate school in the 1980s, he did not choose Harvard University, where his father spent a sabbatical in 1968 and elder brother Hsien Loong did his master's in public administration.

In an attempt to persuade him, his parents sent him a series of articles about "how Harvard is a great institution" and "what it meant to be an alumnus".

Hsien Yang, 57, chose to do a master's degree in management at Stanford University instead.

He is the youngest of the Lee children, after Prime Minister Lee Hsien Loong, 63, and Dr Lee Wei Ling, 60, director of the National Neuroscience Institute.

He described his father as someone who followed what the three children did and gave advice on academic choices, for example, but left them to decide for themselves.

Hsien Yang was two years old when his father became the first Prime Minister of Singapore in 1959, and did not see much of him as a child.

The children would trail their father around the nine-hole Istana golf course in the evenings, and catch up on the day's events over dinner in Oxley Road.

It was only during the family's annual two-week vacations to Fraser's Hill, Cameron Highlands and later Changi Cottage that they saw more of their father.

The parenting was left largely to Mrs Lee.

A conveyancing lawyer at the law firm Lee & Lee, which she co-founded with her husband and brother-in-law Dennis, she would go home at lunchtime to be with her children.

"I think the nature of conveyance work was much more predictable than litigation or corporate law, which can be very intense, so she was able to manage both her legal practice and the family," said Hsien Yang.

A Queen's Scholar herself, Mrs Lee raised three President's Scholars. Both sons joined the Singapore Armed Forces and rose to the rank of Brigadier-General. Hsien Loong left the military in 1984 to enter politics, while Hsien Yang left in 1996 to join the private sector.

Politics was simply not his cup of tea, explained Hsien Yang, who is married to lawyer Lim Suet Fern, 56, and has three sons - Li Shengwu, 30; Li Huanwu, 28; and Li Shaowu, 20.

"My father suggested it but I didn't think it was something I wanted to do. Politics should be a calling," he said.

"I've never seriously contemplated it. I don't know why people think just because I am my father's son, this had to be my destiny."

There was some burden in being the son of Mr Lee Kuan Yew, he said.

"Some people will claim that I got the opportunities because I was who I was," he said.

"I think I've earned them and worked very hard to earn them, which is what I think my parents would have expected."

As a rule, he never brings up his association to his father.

"It irks me that in newspaper reports, even till today, when they mention me, they'll mention that I'm the son of the former Prime Minister or the brother of the current Prime Minister.

"How is that relevant to what I'm doing?"

Interviewed two years after his mother's death on Oct 2, 2010, following a series of strokes that had left her unable to move or speak for two years, the grief he felt was still plain to see.

Tears welled up in his eyes as he recalled how surgery gave her a brief recovery but also left her in a locked-in state for far longer than anyone expected.

He said her illness and death took a great emotional toll on his father, whose health declined as he tried to cope with the loss of his wife of 63 years.

"It was just painful to him, to her. Frankly, I think he aged a lot during that period, and after."