Family relations limit capacity to act
Albano explains that husband and wife cannot donate to one another. The prohibition, extends to common-law relationship. (Art. 87, Family Code) The reason is public policy; the possibility that one may exert undue influence over the other. They cannot also, as a rule, sell to one another, except in cases where they are governed by the complete separation of property regime or when there is separation of properties during the marriage. (Art. 1490, New Civil Code)
Husband and wife cannot also enter into a universal partnership of all properties. (Art. 1782, NCC)
The law also declares as void marriages among relatives in the direct line, whether legitimate or illegitimate (Art. 37, Family Code); or those in the collateral line up to the fourth civil degree of consanguinity by reason of public policy. (Art. 38, Family Code)