Sounds sort of familiar, but can't really think of it. Maybe its one of these:
https://www.mangaupdates.com/series.html?category=Male%2BPregnancy%2509&exclude_genre=Doujinshi&perpage=50
Is this what you mean http://www.mangago.zone/read-manga/jappa_no_amane/ ?
He prays to the moon? http://www.mangago.zone/read-manga/yokubou_shounen/mrs/manga/yokubou-shounen/v-1/3/5/ This one? Called Love Snatcher by Naono Bohra in the Yokubou Shounen manga. Chapter 3.
Wrong one, never mind.. only half the original post showed up at first.. I apologize.
Try the manga 'Sex Pistol', cause two guys can also give birth to a baby.
is it kudan no kuroneko ch. 4? or hyper love power?
Maybe animal x series is what you are looking for.
I cant remember this yaoi manga but they can have a child with the power of love even if they are both guys, i think the otheir guy is not human or something like that in the end their child fell inlove with a man and have their child too. Thankyou guys