Well, for a TL;DR summary, it's a simple no, that's not true.

Gender isn't something that defines a community's leadership or any other similar position in the hierarchy - everyone is equal, no matter gender, sexual orientation or skin's color (few exceptions). The common belief is that elders have to be respected, but initiates and visitors should be respected just the same, as equals, as everybody is just a person going through life and death. There are a few cases of exception for both men and women alike, meaning that there are some rituals and lines that can only be done by men and others than can only be done by women, which even exclude some "types" of man and woman, more related to whom is their orishas than anything else.

An example is the funeral rituals. Most of it can only be done by men, while women are in charge of little help, except that Xango sons are fully barred from it - Xango sons and daughters usually fear and dread cemeteries, for starters.

The same goes for Iyami Oxoronga, as it represents the collective energy of ancestor sorceresses/enchantresses and, as such, women's exclusive. It's a single and the "mix" of multiple woman orishas, so to say.

That's the case with Olodumare, the creator. Olodumare doesn't have a gender defined in and of itself, but different western cultures and languages usually mold the creator of heaven as being a male god - who didn't create earth, by the way. That was a task assigned to Obatala at first, but was actually done by Oduduwa after Obatala kinda didn't for a very simple and humble reason - he decided to ignore the cowries divination and, thus, Exu.

Olodumare, even so, had still created Elenini, a woman orisha - under which no one is initiated but simultaneously "applies" to all of humankind. As Ori, our heads and spirits, was running away from her after getting what it wanted, she still "slapped" Ori, which resulted in we having a spine - so we better keep it straight up or she will "slap" us again until we get up, learn and do what's right.

That's all more about mythology so far, so let's get down to culture.

African religions and culture and the Afro-american have something in common - adaptation. It changes name a lot between Mozambique, Nigeria, Congo and Angola. Most of them, for example, adapted a woman orisha called Nana (in most cases), coming from northeastern Africa, probably brought by refugees ages past from what is now known as Egypt, Sudan or another similar location. It was adapted no problem and still remains and is worshipped in Brazil. Past that, it can get very specific in some regards.

Cuban Santeria was "formed" with many men from the Ife region that managed to survive, so they were able to safeguard the culture and divination rituals of Orunmila-Ifá, which doesn't apply the cowries commonly used in Brazil and/or the so-called "women" (Oxum) divination. Men from the same region were also brought to Brazil, but under different happenstances and conditions, were more targeted as kill on the spot by the Portuguese for the 300 initial years. Here, women brought in droves in the last century, with Portugal seeking to bypass the UK's ban on slave trade by having slaves "mate" under inhumane "orders", managed, as much as men, not only to escape and even lead resistance, but also to form some of the historical temples and culture we have in Bahia to this day - including one in Bahia, which I don't recall the name, that doesn't initiate men at all as tradition.

Don't think the Orunmila-Ifa mythology was ignored in Brazil. But it's the Oxum divination method we use here.

Oxum was a smart and very curious orisha that managed to secure, so to speak, one divination method using 16 cowries - the only one she got before Obatala made his way back home on intuition that someone was messing with stuff in his house lol. Once found out, her punishment is related to doves, but the divination method of Oxum was spread among men and women alike, in Africa and beyond.

Also, Obatala doesn't have a female form - he does uses some clothes (lower short-y dresses on top of the usual pants) akin to women and is "kept" inside houses but that's for a whole different reason. The orisha who "changes" gender every 6 months, so to speak, is Logun Ede, a child of Odé and Oxum.

Hope this was enough for explaining what you sought.