If you have F & M plants and they're flowering, they need some bugs to help fertilize.
If it's warm enough outside to place the plants out were the bugs are, and toss a few banana peels and other fruit parts on the pot, that may help you get viable seed.
A problem with them being inside and them not getting properly fertilized is that the fruiting branch may look like it has good fruit on it but often with empty or undeveloped embryo.
Giving the plant good nutrition (I think it's 2-1-3 NPK, for palms) and providing for their natural fertilization method, will help to produce good seed.
