If that option in the menu is not showing up, there are pretty much just 3 possibilities (and number 3 is by far the most likely):
1) Sim is within a few days of transitioning to elder and so is prevented by game from pregnancy.
2) One or more EPs/SPs are unpatched.
3) Custom content you have is either in conflict or is incompatible with your game configuration.
Try running the Hack Conflict Detection Utility:
http://208.109.175.73/Sims_2_HCDU.htmNote that it does NOT differentiate between benign and non-benign conflicts, but only lists possible conflicting items (and may miss some as well). But it is a good place to start and check what may need to be removed because of conflicts.
After that, it is up to you to ferret out which file(s) need to be removed to end the conflict and restore the menu option to your game. using Clean Installer to either Move or Remove questionable files:
http://sims2pack.modthesims2.com/Be aware that using Remove in CI is final -- it cannot be undone and any file Removed is gone forever and irretrievable. if you've never used CI before, also note that all hacks and hacked objects are highlighted in red, and all duplicate files are highlighted in pink. You can group the duplicates together by using the MD5 tab in CI, and then remove all but one from any grouping of duplicates (only exception is if a group of duplicates is listed as 'Empty Package' in the Type column - in that case ONLY, remove them all).
Also note that if you have a lot of custom content, it can take CI a while to finish generating the full list of that content.
If I had to hazard a guess as to what to look for, would focus on woo-hoo hacks and/or hacked beds first.
Otherwise, the time consuming but tried and true 50% method is the remaining way to winnow down any culprits which are behind your problem:
http://www.sims2wiki.info/wiki.php?title=Game_Help:Finding_Problem_Custom_Content#The_50.25_Method
