Platypus, the preserver of manga history, showed this page he scanned from a 1978 issue of Monthly Manga Shounen (月刊マンガ少年) to me. It was great seeing a manga artist, Minamoto Tarou, acknowledged the importance of Fire! even back then, and hailed it as the grandmother of the 70s bishounen manga.
Here's a quick translation for you.
Monthly Manga Shounen, issue no. 1978/8
Minamoto Tarou
Speaking of show business, when I was watching Yamaguchi Momoe sing “Playback” on TV the other day, I was suddenly reminded of Takakura Ken’s youth. Her dreamy gaze when she sings, how she looks slightly bashful when her song ends... She was almost the spitting image of Ken-san of the past. Is it that there’s something "manly" in a woman’s charm? Or does a man’s masculinity has something akin to femininity?
...And it brings me to the topic of male-male romance manga drawn by women.
Things took off after manga like Mo-sama’s “Gymnasium” or “Thomas”, and Takemiya Keiko-shi’s “Yuki to Hoshi to Tenshi to.” And until now, there has been a plethora of works in that vein, and every magazine you pick up today sure to be full of such works. But when did it really start? When I think about it, Mizuno Hideko-shi shines bright. Yes, I'm talking about “Fire!”
“For the first time in my life, I loved someone more than I did my mother: Fire Wolf.”
Didn’t this whole world came to be in young Aaron’s cries as he was breaking down in tears before the flames of the explosion that killed Wolf? This is what I think.