Isn't it often the case though that in gay couples one is more masculine and the other more feminine? Or dominant/submissive perhaps.

That's probably more important - having both types of personality present?

No, that is a stereotype. Most gay couples don't look like that.

I wasn't talking about 'looks'. I was talking about behavior.

Whenever I see gay couples on documentaries etc, there almost always seems to be one 'feminine' one, and one 'masculine' one. Regardless of what sex they actually are.

Documentaries != real life.

Documentaries are a subset of real life. So there must at the minimum be some couples who fit this pattern :/

Of course, you'll find the same pattern among some straight couples as well. Your original statement that most gay couples fit the pattern simply isn't true, most couples of gay men is two guys living together, dividing household chores in a way that does not follow stereotypical gender roles, and most couples of gay women living together is the same. Hell, even most straight couples I know don't divide household chores that way, or have one partner being the dominant one.

So no, you are not likely to find the "male"/"female" pattern among gay couples, but since it's not even common among straight couples, I strongly doubt it's relevant for raising children.

I'm not sure where you're basing that on.

Most couples have pretty strongly defined roles. For example, if a shelf needs putting up, it's more than likely that the male will be tasked with this. If a daughter is after makeup advice, it's likely that they'll go to their mother rather than father.

Perhaps you're reading way more into what I'm saying than is actually there.

Fair enough, I had totally different actions in mind, but for your examples I can see how those are very likely to be divided by gender in straight households.

However, when it comes to gay relationships, you generally can't make any prediction about who does what or how the chores are divided. The notion that all relationships have (or worse: has to have) a "male" and a "female" is completely unfounded.