The gender changes when a female Super Megaforce becomes a previously male Ranger or a male Super Megaforce becomes a previously female Ranger. In most cases, a skirt is added or taken away. In rare cases, if another female ranger has no skirt, the others in her team don't get a skirt.
Mystic Force - 3
Originally Blue Mystic Force Ranger is female and Yellow Mystic Force Ranger is male, Yellow Super Megaforce Ranger changes the costumes, adding a skirt. Blue Super Megaforce Ranger has blue legs when he becomes Blue Mystic Force Ranger and no skirt. I put it as 3 Gender Changes because of the skirted Red Mystic Force Ranger.
Ninja Storm - 3
Originally, Blue Wind Ranger of Ninja Storm) is female, Yellow Wind Ranger is male and Navy Ranger is male. When Yellow Super Megaforce Ranger became Yellow Wind Ranger gained a skirt. Hurricane Blue lost the skirt when Gokai Blue donned the costume. When Pink Super Megaforce Ranger became Navy Ranger, she added a skirt.
Yellow Super Megaforce Ranger or Pink Super Megaforce Ranger became Red Jungle Fury Ranger in the second episode, a skirt was added. Yellow Super Megaforce Ranger or Pink Super Megaforce Ranger became Red Mystic Force Ranger, skirt was added. This happened in "Super Megaforce."
Originally in Jungle Fury, Rhino Ranger is male, Pink Super Megaforce Ranger dons a skirt when she becomes him. There is 2 Gender changes because we also saw a skirted Red Jungle Fury Ranger. This has happened in "Blue Saber Saga" and "Spirit of the Tiger."
RPM - 1
Pink Super Megaforce Ranger became RPM Ranger Black with a skirt, he is originally male. This has been seen in "Earth Fights Back" and "A Lion's Alliance." It will also be seen in "Power of Six" and "In the Driver's Seat."
Not given a name yet in Super Megaforce but in the original Dairanger, Yellow is male so they added the skirt but since US kids never seen these suits before, they probably assumed Yellow was a girl. This has happened in "Earth Fights Back."
Wild Force - 1
Yellow Wild Force Ranger, she gains a black hem on the skirt because White Wild Force Ranger had a pink hem and Pink wouldn't make sense on yellow so Black is the only natural progression but some people would want gold. In the Japanese series Gaoranger, Yellow was a boy. This has happened in "A Lion's Alliance" and "Spirit of the Tiger."
Alien Rangers - 2
With the Aquitar Rangers, the only female is White, Yellow is male. Yellow Super Megaforce dons a skirt as Yellow Aquitar Ranger. Yellow Super Megaforce as Black Alien Ranger has appeared briefly in the opening sequence and in "A Lion's Alliance."
MMPR - 1
In MMPR, Yellow Mighty Morphin Ranger was female but in Japan, he was originally male and had no skirt because of that. Super Megaforce Ranger dons a skirt similar to Pink Mighty Morphin Ranger. Here there was extra effort as they had to make a stylized skirt with hem for Yellow. This has occurred in "A Samurai Surprise." In the intro for Super Megaforce where the Rangers look up at a cliff with Rangers, we see the Yellow Mighty Morphin Ranger with a skirt.
Time Force - 1
Yellow Time Force Ranger was female but had no skirt because her Japanese counterpart was male, so when Yellow Super Megaforce Ranger becomes her, a skirt is added.
Lost Galaxy - 1
Yellow Lost Galaxy Ranger had no skirt because like MMPR, Time Force and Wild Force, the Japanese counterpart was male. Super Megaforce Ranger dons a skirt. In Gingaman, Yellow was male. This has occurred in "A Samurai Surprise" and "Silver Lining Part 1."
Lightspeed Rescue - 1
Yellow Lightspeed Ranger is the same story, she gains a skirt this time as she previously did not have one. Kelsey was female but no skirt because in Japan, Yellow was male. This has yet to occur.
One half? Yup. Silver Super Megaforce Ranger becomes RPM Gold and Silver in "Six", a mix of Gold and Silver making half of Silver a male suit, with no skirt. This will appear later on in the episode "Power of Six".
Male RPM Ranger Silver - 1
This has not appeared on the show yet, but appeared in a Japanese book featuring the Ranger Keys.
18 1/2 gender changes!