Perhaps it can be simplified as a young mother simply feeling the need to belong.
I mean, let's face it-- those who are non-Greek, yet also have positive opinions of Greek life usually see fraternities and sororities as tight-knit family groups on campus (our internal frustrations aside at times). I was intimidated as heck by the NPC sororities on my campus, yet wanted to be part of one. I decided instead to join TBS as a freshman because the size of the NPC's was a bit too large for my extremely shy, backwater Montana girl self to handle in the middle of Boston.
Being 29 and seeing several of my friends going through marriage and first children in the past couple years... it's amazing how many women, despite having a loving husband and young child... and even close friends, just feel like they're ALONE. Perhaps the desire to connect to a sorority is just a basic need to feel like she is part of a sisterhood of women and to reconnect with life outside of the needs of her child.
And really... there isn't a lot out there for women that are older than 22/23 but younger than mid-30ies as far as organizations to connect to... I have been looking. Part of it is simply our generation, I think-- not as many women want to join post-graduate groups. But for those who do, the options are a bit limiting.
~ Mel.