I find it hot because:
1. it fulfills my primal desire to reproduce
2. it is the ultimate form of conquest/dominance over a woman.
3. I like children, especially those related to me by blood.
4. feels like a winner at life to spread your seed.
5. it is actually useful. it gives you trustworthy companions in life (blood relatives).
6. I find pregnant bellies and lactation immensely sexy.
7. pregnancy hormones make women boobs grow bigger. giving them a more womanly figure.
8. time now works for you instead of against you. so the sooner you impregnate her the better. if you delay you are just getting older and less able to handle kids. besides kids only really get difficult during their teenage years.
What I want to see in a game:
A. assertive dialog about knocking up a woman. none of that fretful child of "oh no I can't be a father. quick take plan B or something". But actual intentional impregnation. Ideally tied to domination.
B. actual real pregnancy. none of that fake "belly inflation" or "pseudo pregnancy" or god forbid "she was pregnant with parasites". But actually pregnant with the MC's biological children
C. normal duration. I dislike how so many pregnancy game accelerate the whole thing so the girl gives birth in 2 weeks. it feels like skipping too many steps. And also forces you to start using contraceptives so you don't get overwhelmed by hundreds of children per waifu. I would much rather the pregnancy progress at a more sedate pace. You are also pressed for time to do all the pregnant sex scenes before she delivers
D. pregnant belly rubs, pregnant sex, and sucking milky boobs.
E. Don't make pregnancy a huge drawback. a lot of games for some reason make it so that you cannot progress plot while a girl is pregnant. even when it makes no sense.
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I also think that it does not have to all be done at once. A lot of authors find it too daunting because they insist on writing the whole thing from beginning to end in one go.
But you could easily split it into steps:
have an update introduce the impregnation itself.
Then a future update add early pregnancy (small belly bump and adjusted dialog and sex scenes)
Then a future update add late pregnancy (full sized bump)
Then a future update add birth and introduction of baby.
You don't even need to do all the steps. could very well leave the baby to the epilogue.
) you need both together for the breeding to be as hot.
