Sims 4 'try for a baby' not working for same sex couple

Are you using mods ?

Is there enough space on either side of the bed ?

I am using mods, and there is space on each side of the bed, but am experiencing the same issues.

@lulumi2209. It can be explained in a number of ways: your household is already full; the sims are already pregnant, there is something the matter with the bed they use, if you changed the settings in game like the OP in this thread etc. 

But the reason for the question on mods is that the first step should always be to exclude their influence. And depending on the creator's decisions some mods can be very pervasive and will effect a save even if the mod folder is removed and cache cleared; so trying in a brand new user folder is recommended:

In Documents\Electronic Arts find your The Sims 4 folder and rename it (example: The Sims 4old); and launch your game. A new folder will be created without any of your saves, mods etc. Create a new couple in CAS, making sure their settings each are Able To Impregnate/Able To Be Impregnated; and with them Try For Baby. Let me know how it goes. 

Here is a longer explanation on what resetting the user folder means:

https://sims4.crinrict.com/eng/2014/09/resetting-the-game-to-factory-settings-without-reinstalling/