HONG KONG • Nicholas Tse once said he did not want his then wife Cecilia Cheung to return to work after she gave birth to their first son, Lucas, in 2007.

Noting that bringing up children is a mother's biggest job, he added: "Perhaps some people will think we are sacrificing too much for the sake of our son, but I think giving up a career for our son is the right thing to do."

The couple married in 2006 and filed for divorce in 2011.

Media reports surfaced then that he was upset when Cheung took Lucas to a filming set after she started work again. He himself was lambasted by many for not spending enough time with Lucas and Quintus, his second son with Cheung, focusing too much on work instead.

The couple have joint custody of their kids.

Perhaps it is Tse's yearning for an ideal, stable family life that explains why he is now upset with his sister Jennifer Tse.

The latter, who stood by him during his bitter divorce with Cheung, has chosen to be a single mum, giving birth to a daughter recently.

According to a Yahoo HK story, the siblings are not speaking to each other after she rebuffed his demand that she marry the man who fathered the child.

His identity is not known, but netizens speculate he is American actor Jeremy Renner or someone from the Chinese community in Vancouver, where she is reportedly bringing up her child.

Talk has it that Nicholas Tse, 38, fears his sister may bear the stigma of an unmarried mother. He is also wary that Jennifer Tse, 36, a model-actress, may not have the financial resources to give both mother and child a comfortable lifestyle.

But she feels that marriage is no guarantee of bliss, given that he himself suffered a divorce.

Some wonder if the rift between the siblings became so deep that she chose not to attend a Chinese New Year reunion dinner with their father Patrick Tse, though Nicholas Tse showed up.

Asked if there was any truth to the reports of a dispute, Nicholas Tse's manager did not comment but, tellingly, did not issue a denial either.

Netizens are divided over the issue. While some think Nicholas Tse is right in thinking that his sister would find it difficult to attract a new romantic partner, given that she has a child, others feel he should just reconcile with her and become a supportive sibling and uncle.

But Nicholas Tse should at least be happy that Cheung, 39, is totally focused on caring for Lucas, 11, and Quintus, nine. Noting that acting is now secondary for her, she said she accompanies them to school and takes them on shopping trips.