I think this is stupid but that is probably just me, anyway, change the setting to your preference. The gender of the Repairman, once assigned the gender cannot be changed unless the Sim is culled. The gender of the Pizza Delivery Sim, once assigned the gender cannot be changed unless the Sim is culled. The gender of the Mail Carrier when KW Mail Carrier is enabled, the NPC is created/assigned at the beginning of a new game and once assigned the gender cannot be changed unless the Sim is culled. When disabled the normal Mail Carrier situation will run, if this setting is changed after KW is started you will need to save/load.
There is a new Loverslab menu in Kinky World -> Settings, I also made some other changes, most of them can be toggled on/off if you don't like them. I made some changes to get rid of the lag the mod seems to be generating on modern CPUs, I have eliminated most of the lag generated by KW but there are still the occasional 'hiccups' now and then that I haven't been able to isolate yet.
