I'd have to place myself in the no a/s/l ctcp crowd. I do not participate in channels where age, gender, or location are relevant to the topic or theme of the channel. When talking in #mIRC does it really matter what age or gender someone is? Does their bio somehow validate or invalidate their contributions?
I have always thought that asking that to the channel is extremely rude. The sole purpose of asking is to rule out people based on their age or gender so one can more easily move on to desirable targets and engage in private messages. Sending "age/sex/location check" or a ctcp that does it is the same as saying "excuse me, i know i just joined, but I must execute a filter on all of you to determine who is worthy of my conversation. Sorry in advance to those who don't make the cut." I think the reason that some want it a part of irc (like an extra whois field) is so they can perform this filter without announcing to the channel what a jackass he is. Unfortunately for them a ctcp wont be quiet enough.
I can't support a process that makes this easier or encourages it. If mIRC were to put this in (a ctcp) the first thing i would do is script an auto kick/ban/ignore on those who do it and those who respond to it. On the other hand, it might make those ircds that don't have a channel mode to block ctcps rethink it. Anything else (like an extra whois field) would require a change in the server as well as other clients. I think that is as likely to happen as a MatchMakerServ on EFnet.