Unless it's a certain strain ( IE-WMD or Jack) any reddening of the stem is usually a sign of some stress. having said that I wouldnt worry about it too much, but know that it was probably caused by a period of too little light, low temps during the dark cycle, a micronute deficiency or the like. It is minor, and i just want you to be on the look out for any other signs that something is going wrong.
Your pics though look like healthy girls, the white spots are pretty normal, and overall I'd say no worries. The "male part" is prolly a calyx and will open up...again keep an eye on her.