Employees in the private sector as a full time or part-time you the right to 4 months of parental leave per parent, which can be taken full-time or part-time depending on their needs before the child is 12 years old. It is necessary to have worked for the same employer at least 12 years to apply for this leave.
This leave is non-transferable, meaning a portion of this leave cannot be transfered to the other parent and is paid according to a flat rate. http://www.onem.be/fr/documentation/montants-baremes/interruption-de-carriere-credit-temps#16309
For more information:
http://www.werk.belgie.be/defaultTab.aspx?id=547
http://www.onem.be/fr/documentation/feuille-info/t19
For employees in the public sector, other rules apply. Please, check on the website of the Rijksdienst voor arbeidsvoorziening (RVA)/ Office National de l’emploi (ONEM):
http://www.rva.be/nl/burgers/loopbaanonderbreking%20en%20tijdskrediet/loopbaanonderbreking#8294
For self-employed or freelance workers however, other criteria apply. It It is best to contact the mutuelle that provides your coverage.
For more information on parental leave in general: