What is the ruling on intentionally emitting semen in Ramadan while having doubts about the validity of ghusl?

Masturbation is forbidden (haram), and its prohibition is more severe in Ramadan, and even more so during the daytime in Ramadan. Whoever commits it must repent and make up for the day on which it occurred if it was during the daytime.

As for ghusl (ritual bath), if it is merely a doubt, then there is nothing upon him. However, if he strongly suspects that he did not perform the obligatory ghusl, then he must repeat the prayers he offered with that ghusl, and perform the correct ghusl with the intention of رفع الحدث (removing the ritual impurity).