This article clarifies marriages which is not valid due to the following reasons:
1. Contract by parties below 18 years of ages.
2. Solemnized by person with no authority
3. Solemnized without a Marriages License
4. Bigamous or Polygamous Marriage
5. Contracted through mistake of one party as to identity of the other
Source Art. 35 of the Family Code of the Philippines
Haha! at number 5 =P
Maybe someone needs to have their eyes checked. =P
Ok... maybe it can happen to identical twins...
Don't be shy to leave a comment it's more appreciated