There was definitely a time, maybe a few years ago in the 2013-2014 range, when opening a new Gmail account required a phone number to activate[1]. The rule wasn't applied to every one, it was based on some heuristic or another.

Though, amusingly enough, you could use a Google Voice number and there was no limit to the number of accounts one number could activate (at least not that I noticed).

1 http://timesofindia.indiatimes.com/tech/tech-news/Google-Yah...

The reason why I make my throwaway email accounts with gmx.com is because when I tried to create Google or yahoo addresses they both required a phone number. Yes, I am aware that wasn't a requirement 10 years ago. You also got my gender wrong.