Re: Star Wars Episode 7 - 2015
And let's remember they are in no way bound to the EU, so they could easily give Luke a sole female child for these movies (or alternately - and perhaps more plausibly - the girl could be his granddaughter.)
Why would that be more plausible? It's been 30 years since Return of the Jedi. Even if Luke impregnated a woman the day right after the death of the Emperor any daughter of his would be around 29 and any child of hers would probably be around 10 at best.
"Konrad Curze, be at peace. I have arrived, and I intend to take you home."
"That is not my name, father. I am Night Haunter, and I know full well what you intend for me."