Hmm... Good and very interesting question. I don't think that I'm gonna give a really good/informed response coz I'm kinda out of the loop (and I mostly follow the more mature groups in JE) but from my understanding, this is how it goes...
JE's stand with their idols having relationships is the same as any other agency coz most of the time when there's a rumour coming around of one of their idols dating someone, more often than not a denial is issued. I am not 100% sure of this but I think towards famous couples like Nagase Tomoya/ Hamasaki Ayumi, Inohara Yoshihiko/ Seto Asaka and previously Kokubun Taichi/ Aiko, the agency's stand is neutral, i.e. they don't comment or get involved in it. If my memory serves me well, even in the latest big dating news in the JE scene (which is between Shonentai's Higashiyama and the actress Uchiyama Rina), it was the girl's agency that acknowledged the relationship, not JE...
In any case, my personal feeling is that the Japanese media and public in general are more forgiving towards the males. (Unless you're Kondo Masahiko, but then again, he's still around and with a career... )
If you want to talk about dekichatta kekkon, JE's most famous example is Kimura Takuya who married Kudo Shizuka coz she was pregnant with his child. Given that he's still in JE and still very much popular in Japan even though he's now a father of two, I would say that yes, their public is still very receptive towards males idols moving on with the normal course of life of mating and starting families.

But that said, the parties involved were already full-fledged adults by the time they got pushed into marriage coz of the kid...
I don't know as to why there's such a difference between the treatment of male and female idols really... My guess is that the shelf life of a female idol is very much limited hence, if they do anything to jeopardise their careers while they are still young and marketable, the agency will react quite adversely to it coz the females don't have the luxury of time to recover from scandal? Either that or their ideal female is one who is virtuous, pure and clean and therefore any open involvement with males would give them an "unclean" image hence making them less marketable than they would have been?
Saa.... =P