The Duke of Cambridge has highlighted how the Royal Family had "little concern" about acquiring ivory, as he called on China to help save endangered animals.
William said he was not judging his ancestors, in the same way as Chinese doctors who have spoken out against the use of animal parts in medicine were not condemning their predecessors, but stressed: "We have a responsibility to act on the facts we have today".
His words came in an address recorded for the popular Chinese TV show Let's Talk.
William said if African elephants continued to be killed at the current rate of 54 a day, there would be none in existence by the time his daughter Princess Charlotte was 25.
Appealing to a potential audience of around 100 million, who are expected to tune into the pre-recorded programme when shown at a later date, the Duke said: "The desire to possess animal trophies, or ornaments made from ivory, has been felt on every continent for centuries. I know this topic is sensitive for many families.
"For example, until 100 years ago my ancestors were among those who had little concern about acquiring ivory, without the knowledge of the threats of extinction, corruption, and violence that the ivory trade would lead to."
China is a huge consumer of ivory and the trade in the animal product threatens wild elephants with extinction as poachers feed the demand in the Far East.
Last year William reportedly said he wanted the ivory kept in the Royal Collection to be removed and destroyed.
The Duke has campaigned with ex-footballer David Beckham and former Chinese basketball star Yao Ming to end the trade in ivory and other products.
He raised the subject of the illegal wildlife trade during his meeting earlier this year with Chinese president Xi Jinping, whose country, at the time, imposed a one-year ban on ivory carving imports.
The Duke added: "My rejection of ivory today is not a judgement of past generations. It is an acceptance of the world as I find it today and the world I want my children, George and Charlotte, to inherit.
"Likewise, those doctors and medical practitioners in China that are speaking out against the use of endangered species in medicine, they are not judging previous generations who did not have the facts that you do today.
"They are just accepting the truth that all credible evidence and scientific research shows, for example, that rhino horn cannot cure cancer."
The programme was filmed at King's College London and William was followed by four others, Sir David Attenborough, former Chinese basketball star Ming, and adventurer Bear Grylls.
The Duke told the guests, who were mostly Chinese students attending King's College: "In the 33 years since I was born, we have lost around 70% of Africa's elephant population. Of those that are left, 20,000 are being killed every year - that is 54 elephants killed every single day.
"At this rate, children born this year - like my daughter Charlotte - will see the last wild elephants and rhinos die before their 25th birthdays."
The Duke's speech will feature in the prime-time Let's Talk programme which will be aired on CCTV1 - the flagship terrestrial channel of the state broadcaster China Central Television.
William began by speaking Chinese telling his audience, who are likely to be young Chinese: "Xiexie (thank you) Hen gaoxing he ni jianmian (I'm pleased to meet you)."
And towards the end concluded with a direct appeal to the Far East nation: " I am absolutely convinced that China can become a global leader in the protection of wildlife. Your influence in the world means you can change the face of conservation in this century."
After making the address William said: "It's been a fantastic opportunity to speak to so many millions - hopefully - Chinese people in their homes.
"I see that as a huge step forward in the progress in trying to connect with the Chinese people about this issue."
He added: "It's a big fight, it's a big area, it's international, but I hope this is one small step again towards the progress which I know we can win."