Well, theoretically(and some experiments have shown promising results) it is possible for same-sex couples to have children(genetically speaking), but there are some things to consider, depending on the method used.
If we take a female-female couple as a example, one of the methods used would limit the child's gender to always be female, since the cromossomes would always be xx, and to make a male child, it would take a xy variation, which is non existent in this case.
Now, other possible method would allow both genders, but it would be a little tricky since it consisted in altering some layers of the egg so the fertilization of another egg would be possible.
Still, even if it the most efficient method was already decided by the scientific/medical community and properly tested, this would not be cheap at all, I guarantee. Just the usual artificial insemination is already expensive. A new method like this would be way higher in its price, so those who actually chosen to do it probably would be people who either worked pretty hard for it or were already rich.
So no worries, guys. Men wont be obsolete or anything crazy like that. Lets all keep in mind that there were a bunch of folks whom gone nuts when the (commom) artificial insemination was annouced, all saying that people would just stop having children "the normal way" because of it, screaming non sense like "the end of times". Lo and behold, we all know that this isnt the truth, and they were nothing more than crazy nutjobs.
Note: No, it would not and it wont ever be possible by the scientific community to allow someone to self impregnate. Its antiethical in all its extremes and no one would do it and lose their entire carreer. So, no one can use this argument as a justification to block said research for same-sex couples.