Sims Genes

[Ricalynn]

It's not negative traits assigned, just random.   A lot of times it will be a trait from a parent or a grandparent which is why it's in the coding I included on my last post. 

And I've managed to have a Sim get both his grandfather's eye color and skin color but you're right face seems to be a blend of parents features.   

I will repeat - I did include the exact coding for genetics in my last post.   Beyond that coding, there is nothing else the game will pull from so the information is there.   If it's not there, that means it won't get passed down/shared because the game isn't coded that way.

[lily87]

I'm in the 5th generation of my muddled-up Immortal Legacy, and my heir has the same reddish-brown hair as my founder.  That could be because I saved the colour in CAS, though. 

Also, whenever I've had to accept random traits for any age, I generally get ones that don't help in any way, but aren't necessarily negative (Childish or Vehicle Enthusiast, for example).  It's entirely random.  Although the number of townies with negative traits in my game is astoundingly high.

[Turoskel]

I used Hannah & Aiden Jones for my townie dynasty founders, Hannah has brown hair and Aiden has red, I was hoping to get some flame haired kids from Aiden but they had five children and all got Hannah's deceased mothers black & white streaky hair. First grandchild got it as well and I thought maybe it would keep passing down but his daughter got her grandfather Travis McDermotts blonde hair, and now her son has his fathers black hair. Be interesting to see if it ever crops up again as I go along though.

I think generally as far as weight and fitness go sims tend to revert back to the slider position they have in CAS over time if you don't keep it up. But I have noticed that if a teenager builds up muscle they will often carry that through into adulthood. My own example for this as i've played him such a lot is Dallas, he is on the slim side normally as a young adult with little muscle tone, but if he has used weights a fair bit as a teen and built up some muscle he is a more muscular adult when he ages up and it stays even if he doesn't carry on exercising. I'm not really sure you can affect weight this way but it seems to work for fitness.

[Janna]

I agree that they will revert to the setting of the slider from CAS, whether game or player created.  As for the muscle, I have noticed that the children of the sims that I create are nice but not hotties; both parents I give nice bodies, females are what I see as good and males are hotties; they are not over the limit of muscle, but very nice.   I confess, I love to read romances and I want my sim to look like the guy on the cover, yummmm.  Their offspring, especially the males, have nice muscles but to build them up they have work out; not every day, but quite often.  Same with their offspring, nice but not flashy, but if they work out, niiicccceeee, like their parent. 
In the weight area I have notice that the three males who became pregnant, even though they had the great bods before being pregnant, retained some of the enlarged stomach and lost some of that body builder look; they had what I would call love handles.   Daily working out will get them back in shape and martial arts doesn't count in that area.  Changed the slider back to what it was before pregancy and two or three days later without working out they went right back to slightly chubby when he didn't work out for a few days.  Checked slider and it was slightly past the middle range.   He will have to work out every day now.