The definition makes it a verb/adjective, "acting
maternal," which is chosen behavior. So you're saying {mamta} means "x1
breast-feeding parent who tends to act domestic"? That means a lot of
mothers I know are not {mamta} under the parameters you just gave.
I merely gave a non-exhaustive list of behavior considered maternal. {mamta} means "x1 bears/mothers/acts maternally toward x2," so if
these unmaternal mothers bore children they are nonetheless {mamta}.
The definition seems drafted to include adoptive mothers. A boy raised
in the wild could correctly say: {mi se mamta lo labno}, assuming that
he hadn't stayed in the wild too long to outgrow the capacity to aquire
any language, let alone Lojban.
Plus it seems a man can be a {mamta} because they can act maternal
while not being biologically a mother. But in the real world this is
figurative and {pe'a} should be applied accordingly.