There is this not-so-recent trend in feminist circles that consists of condemning all relationships where the male partner is significantly older (20+ years) as abusive and wrong but at the same time celebrating as feminist, empowering and wonderful the relationships where the female partner is significantly older.
Of course, all people are different and all relationships are different. It is more than possible that a much older partner will get taken advantage of or abused by the younger partner. There is also a possibility that nobody will end up being abused or manipulated. Relationships that have such a significant age disparity are, however, often problematic. I, for example, would never be tempted to have a relationship with someone 20 years younger. For one, because it would make me a pedophile. I wouldn't even consider being with somebody 15 years younger either. I have a tendency to be pushy, overbearing and intimidating, so I have absolutely no doubt that it would take me just a few short days to bully any guy of that age into complete submission.
As we grow older, we accumulate romantic and sexual experience, financial and professional resources, interpersonal skills, etc. As a result, it is often (not always, by any means, but often) very easy to manipulate a younger person to serve our needs. This possibility, however, is not gender-specific in any way. People who claim that only older male partners can be manipulative and abusive while older female partners are completely innocuous are proceeding on the basis of the patriarchal stereotype that denies women any agency. In their worldview, a woman is not really human. She is incapable of being a bully, a manipulator or a victimizer by virtue of her gender. I, for one, fail to see how having a vagina can inoculate one from all these qualities.
I wish my fellow feminists stopped treating women as if we were constant and eternal victims in absolutely every situation under the sun.