1) Destroy the institution of marriage, make it a joke.
2) Destroy the whole concept of man and woman, muddle the lines.
Of course the end result will be less children, breakdown in traditional families.
The first point is more or less complete.
The LGBT agenda, let's see how far it will go as its having massive pushback from many people in the west.
Ah yes, there were never any gay people before it was somewhat accepted, there were just lots of spinsters living with their friends, who couldn't possibly have been gay because they often had a couple of men around for the evening, and all those old graves from hundreds/thousands of years ago with the men or the women buried next to each other in the same manner as married couples in the culture were just friends*.
And it's weird how something as simple as a couple holding hands or being acknowledge as being legitimate is enough to make someone gay, but before that was visible it you still had quite a lot of people who were gay (just usually not admitting it in public).
In other news accepting that left handedness was not the sign of the devil and punishing people for being left handed led to it becoming fashionable for people to be left handed, you can tell because the number of people reporting as being left handed shot up when they stopped getting beaten as children for using the devils hand.
Back somewhat in reality, back in the "good old days" there were a huge number of very unhappy marriages that one or both parties involved just suffered through (although historically women were known to be creative in dealing with abusive husbands, always a risk when they deal with the household tasks such as poisoning pests and cooking**), which is known to definitely not be great for anyone involved, including any children.
*There is a whole meme in archaeology about that, because so many graves and depictions of what were obviously gay couples were identified as "just good friends", and much of the history was very deliberately mis filed or mis translated (IIRC there is a bit of a joke based on the idea that the reason being gay was illegal, but not being lesbian was because someone who needed to sign off on it didn't believe it was possible).
**IIRC the number of "unexpected" deaths of married men dropped a bit when divorce became a legally and socially acceptable option that the woman could initiate without permission for the husband.