new member of meetup

When Mom first bumped up with mom's club members, the first impression was very good.
Then, every week, one member will introduce herself. We have an IBMer(never left
Florida before), a technical project manager (also a scrapbooking consultent and a wantna to
be travel agent like myself), a private jet pilot controller(a French language major),
a photographer(business owner), a car crash investgator(have 10 different kind of
 jobs before),  a HR personnel, a WIC breastfeeding consultant and few housemaker
like me now. The life story is 200% completed than our fellow chinese mom's group member.
i.e. something like current husband is ex-husband's friend,  Lady A works for Lady B's
 mother-in-law, etc. Who cares?  
Until now, we have a new member joins in, a registered domestic partner.

Mom is a open mind person and used to work for a project lead who is a domestic
partner, and used to sit next to another domestic partner at the office, and used to
attend a party that hosted by a domestic partner.  

Mom's question is how to explain to Miaomiao about domestic partnership. Mom
heard a bill about gay marriage is currently running among the senate, congress
and president. So, it is going to be a big challenge to Mom to answer Miaomiao's
question " why Cooper has 2 moms?"