Sever pruning can transform a male to a female plant. We have reached out to Papaya people so perhaps we can get more information. But this from a 1914 publication

"There is little necessity for pruning papaya trees. Some plants show a tendency to send out side shoots, and it is advisable to remove these or the nourishment will be diverted from the fruit crop on the
main trunk. When the latter has borne for two or three years it may be cut down, and some of the side shoots may be allowed to form a new top, which will continue the bearing life of the tree and
produce easily accessible fruits. Changing the sex of a male tree has at times been brought about
by severe pruning. Removing the terminal bud or even cutting off the whole top below the leaves has been known to bring about this but such treatment cannot be depended upon to do so"
From page 10 of this publication http://www.ctahr.hawaii.edu/oc/freepu...

This due to way sex is determined in the plant. Hopefully we can get more details for you