Long story short, this family's mother secretly gave up a baby when she was sixteen, and all the family found each other and they are going to meet at the end of the month for the first time. This lady is bringing her family (kids, hubby) back with her for this occasion, but I have NOOOO clue what to write on the cake!! Any good ideas? It is the end of this month....

Some of the more talented decorators might have a better answer than me but I would simply write "Welcome." I think it is a simple warm message.

you could do a tree cake and have an additional branch put on it... and something like... "welcome to the_____ family tree".... or "we went out on a limb to find you"....

ok so they're a bit corny... :p

Feefs, I like your idea!

What about "Happy Family?" Makes me think of Chinese food...

Personally I do not know if I would write anything on the cake unless the family has asked you too. I would do a nice cake, whether it is summery, or a gift cake(family is a gift etc...), garden with flowers...

I would speak with the family on what their feelings are about it, it is a very emotional time and sometimes simple is better