Wrong...
The child will take on the citizenship of the parents, depending on the citizenship rules of the parents country (or countries) of citizenship.
In practice, the child will need to get a passport (of their parents country of citizenship) straight away, and then apply to Hong Kong Immigration Dept for a Visa. This visa will reflect the conditions of stay of the parent(s). When a child is born to foreign parents (non-Chinese citizens) they are given a temporary visa for 14 days with reference to the Hong Kong birth certificate number. This is not enforced, i.e. they won't come to your home and deport the 2 week old baby, however, you are expected to get the passport and visa without delay.
The child will not get right of abode unless the parent has permanent right of abode or is a Hong Kong Citizen.
If a parent holds a permanent ID card, this will be reflected in the child passport so the child will have the right to live in Hong Kong until he/she gets their own permanent ID card or until they reach the age of 18.
Foreigners can never gain Hong Kong Citizenship unless they meet the requirements for Chinese Citizenship - in essence if you are not ethnically Chinese, you will not get Hong Kong Citizenship even if you are born and grow up in Hong Kong.
Depending on the status of citizenship of the parents, it is wise to check out the right of abode of the child born in Hong Kong, because in some cases, the child may not be entitled to right of abode in the country of citizenship of the parents (for example if both parents themselves were not born in their country of citizenship). In Hong Kong this can result in the case that the child does not have right of abode anywhere!