Newest version definately feels like it has a memory leak or something. Totally slowing to a crawl every couple of minutes.
Oddly enough, saving and preparing to quit and relaunch the program seems to fix it. Not sure why.
I have never played on phone, so cannot comment. On PC, however, I have not once noticed any lag on any version of the game. So whatever it is, it is not universal. Which makes it tricky to pin down without a lot more detail to work on.
It's the same on PC. Game gets progressively laggier the longer you play especially if you start clicking through things quickly. Quitting and restarting helps so it definitely feels like some sort of memory leak or something, no idea how exactly the game is programmed but I've noticed definite performance issues. Not unplayable though
Suggestion: Pure Virgin could be an option like Baby crazy/Child free, instead of automatically replacing Virgin if it's still there after the first season.