Vaxalon said:
No, you misunderstand.
Maybe not every year. Every other year.
It takes an average of 20 months for ANY woman to get pregnant.
Take all of the penalties, slam them all together. Con 3, nursing, 45 years old, it all doesn't matter.
After an average of 20 months, she's pregnant.
Maybe I didn't make it clear... you still have to make the confermation roll.
Lets add the modifiers...
Normal roll needed (no counting critical sucess)... 15+3(con)+2(nursing)+1(age)=21... she need a critical... lets apply it to the confermation test... DC10 (didn't mention this) + 6... she needs to roll above a 16 this time. okay... now what do we have...
1/20 x 4/20 = 2/400 or 1/100
So she has a 1 in 100 chance of getting pregnant with the stats you gave. Will that woman have a baby with what you gave?
No bloody likely.
Now, lets try a normal woman, no birthcontrol who doesn't WANT a baby but is not adverse to the idea... Lets say she's age 25 with 10 con
She has no con bonus and a + 1 for her age. She has to roll over a 14, and after that, over a 9... lets see...
6/20 x 11/20... a solid 17% chance.
Now, lets try you normal PC level character... lets say a level 5 half-elf mage with 12 con.
+1 for her con.
now say she's in the optimal age of fertility giving her a +1
as a half elf she's between human and elf making her a member of a low fertility race giving her a -2
now lets reasonably she's been knee deep in dungeon muck for the last week (not exactly an enviroment where you git jiggy with it) a -1 for only 2 weeks of activity.
Now, finally, as a responcible woman who is not dumbass enough to rish pregancy with her profression, she uses magical contraception 5/2 + 1 = 3.5... lets boot that up to a 4 by rounding.
first roll = 15 - 1 - 1 + 2 + 2 + 4.... 21... only on a crit.
Now with the second roll we remove the situational modifiers, as it repersents not if she concieved but it the conception takes (IE: she's not just "late")
Second rold (if we get said crit) 10 - 2 + 2 = DC10... Her health and youthfulness cancle out her racial infertility.
So, 1/20 x 10/20 = or about 3% chance of pregency... contraception works, but it's not totally idiot proof. There is still a chance even if your careful.
One more... lets say a lady paladin, slightly past her prime who has found her soulmate and is ready to retire...
No old yet, but pst her prime... +0
A fighting class, so a high con is likely, lets say a 16... +3
She wants a child and they're trying. +2
She
really wants a baby so she has a level 12 cleric friend cast a fertility spell on her... +7
1st 15 - 12 = DC3
2nd 10 -3 = DC7
17/20 x 13/20 = a massive 55%