Pregnancy test through WW sex - NPC

[Gylaran]

So i tested pregnancy through WW sex interaction with NPCs i have no serious relationships with, set probability to 100% and the result... Well this part is either bugged or not coded well. I impregnated 4 females. Looks like 100% is not really 100% and one, after notification that she may be pregnant, she wasn't. Maybe the problem was 3 people in the household and 5 horses? I don't know. The other 3 females had baby, but my sim was not a father. I continued the test with one of those who gave birth already and after 2 days no sign of pregnancy, even when game keep saying that pregnancy appears after one sim day, if the sim is pregnant. It looks like sim cannot be non-household NPC, or at least we need to be partners/married couple, if she want to have my sim's baby. If the female NPC have relationship/marriage already, the baby is automatically considered her husband's. Does anyone have experiences like this, or i doing something wrong?

[Fragnarok]

I have pregnancies set to realistic and all WW sex partners create the correct parents, even if they are strangers or one is a NPC. An important aspect is that you have also turned off pregnancies in Neighborhood Stories. Otherwise, female characters will become pregnant the normal EA method and can't have a child at the same time via WW. Keep in mind that first trimesters also don't really have a visual difference, making it is easier to double check with MCCC.