I have a question/questions about pregnancy duration and age differences between several babies (at least two).

Let's say I have first baby and I want them to be one or two years (one or two days in sim's life) difference from second baby.

How do I do that?

That really depends on the Life Span you have and the number of days in the baby and toddler age groups but a rough guess is to wait till one is a toddler or half way between toddler and child

1-2 sim days apart is really close, but it does depend on their life span as namaradus said. You would have to have a really short pregnancy term to allow that to happen (< 3 sim days), plus just around no cool down period between pregnancies. It might be easier to just adjust all of their ages accordingly with MC after they are born.

Does it depends on how many days for pregnant?

I thought it was, wasn't it?

The default pregnancy hours is 72 hours, right?

So, when my sim get pregnant and born baby, get 2nd pregnancy right away, then after 72 hours, the 2nd baby is born, right?

Life Span I'm using: 90 Days

Number of days in the baby age group: 2 days (0-2)

Number of days in the toddler age group: 6 days (2-8)

That sounds about right after the first one is born have her get pregnant again within an day or 2

Bottom is my Life Span Setting for one ofActive Family that I play:

My Edited Version of EA Default
Baby: 2 days = 0-2 Years old
Toddler: 6 days = 2-8 Years old
Child: 5 days = 8-13 Years old
Teenager: 5 days = 13-18 Years old
Young Adult 22 days = 18-40 Years old
Adult: 28 days = 40-68 Years old
Elder: 22 days = 68-90 Years old

I chose above so that I can make sim age almost like real life.

Is there ways to change the pregnancy duration according to what I set as Life Span?

There is a way to change the pregnancy time but that requires math I am not able to figure out I'll have to leave that to some else a little more savvy on that

You'll need to register for an account or login to an existing one to see the mod but Twoftmama at TFM has shorter pregnancy mods http://simsasylum.com/tfm/index.php?/to ... er-8-2012/

Oh, thanks for the link.

Can it be done using Nraas mod?

Yes it can be done with Retuner but that requires changing several different values and the math has to be exact right on as well as terminating all existing pregnancies before doing it