there are several reports of people stressing the plant to change its sex
i dont think it works every-time, but it may be worth a shot.
some people drive a nail in the trunk, some just cut the top 6 inches off.
there are reports of them changing sex with lack of water also.
also, while these look like male flowers, its not impossible that you will get fruit.
there are something like 7 types of flowers (3 main types = male, female and Herm)
the others are more rare, but still happen on occasion...
papaya sex can be complicated. LOL