Even in a city with a multiplicity of billionaires, the urging of the leaflet seemed a little hopeful: 'Donate hundreds of millions at a time.' However, it wasn't dollars it was soliciting, but sperm - and just one small donation contains hundreds of millions.
The leaflet was produced by the Family Planning Association in support of its semen bank, but it failed to do its job, with the bank closing two years ago after a decline in the number of donors.
Consigned to history, it is now reappearing among a plethora of items in an exhibition to celebrate the 60th anniversary of the association.
The association was established in 1950 to promote family planning and contraception and to provide advice and treatment to Hongkongers troubled by problems or illnesses related to sex or reproduction.
Humour has always been an important element in its campaigns, given the need to get messages across to the public about tricky subjects without being pornographic, according to executive director Susan Fan Yun-sun.
For example, a plastic bag for containing wet umbrellas on rainy days was introduced a few year ago printed with the words 'Keep it covered, use a condom' to promote safe sex.
Along with the bag, old tools for contraception will be on display at the exhibition, including applicators for implanting intra-uterine devices, and equipment for detecting blockages in oviducts.
Other exhibits reflect changes in society, such as under the large inflows of new immigrants from the mainland unfamiliar with the ways of Hong Kong. As well as family planning information, the association printed reminders such as 'please bring along your ID card when you go out' on its leaflets in the 1980s.
The slogan 'Two are enough' was introduced in 1975 when the city was in the midst of a population boom. That seems a far cry from today, with the city's birthrate shrinking and Chief Executive Donald Tsang Yam-kuen calling on parents to have three children.
Statistics show couples had an average of 3.3 children in 1972, but that had dropped to 1.6 by 2007.
Fan said any number of children was appropriate as long as couples planned them before it was too late.
'Couples now prefer to have a house, a car or a promotion at their workplace before having children,' she said. 'But when they are over 30 years old, they could face difficulties in giving birth to a child.'
The optimal childbearing ages for women were 20 to 35, she said, and if they had their first child over 30, it could be hard to have a second.
The exhibition runs from Thursday to Saturday at the Institute of Education in Tai Po.
In 2004, the Family Planning Association received 1,240 inquiries regarding problems about childbearing. In 2008, the figure increased to: 1,890