I used to post casual encounter ads on Craigslist and one of the responses I received was from someone who claimed that she and her husband were looking to start a family but were having issues due to his low fertility so they were seeking someone to donate sperm ... as nature intended.
A quick reverse image revealed that they were "borrowing" images from a couple who produce amateur cuckold porn, Google "Milf Becca". They're also on Reddit as u/youngtexascouple. I have to admit, considering what they were proposing, stealing images of people who produce that type of content was a nice touch and they were using more creativity than the usual assortment of spammers/scammers, pic collectors, time wasters and predatory gays I typically received responses from.
Something else that set off my bullshit alarm was their claim that they live in Vaughan. If you can afford a house there, you can afford even barebones fertility treatments. And if buying a house has left you so broke that you have to turn to "alternative" methods to get pregnant, then maybe you should get your savings built up a little more before you start a family.
I also realize that if they had been a real couple and I had gone through with it, I would have likely been thoroughly screened, tested and had to met them a couple times before the wife and I spent naked fun times together. But, starting a family is a huge step for a married couple and I have a hard time believing that they would ask some random stranger they met online, on Craigslist no less, to father their children. Yes, I would basically just be a sperm donor, it would just be taking a more ... direct approach but at the same time, why not turn to someone they knew if it wouldn't make things too awkward.
I also get that there may have been an element of cuckoldry involved, more on that in a minute. Maybe the husband wanted the shame and humiliation of knowing that he would be raising another man's children, someone his wife hooked-up with via a site as sketchy as CL no less. But, again, why not turn to someone they knew, one of the wife's boyfriends or, and I know this term is frowned on, their "bull" if they had one. Hell, the husband could have been on hand for the children's conception. This also threw up a lot of red flags since they would have been making their children a part of their kink. If I had gotten even a whiff of that had it been a real offer and not an attempt to get me to sign up for a Adult Friend Finder clone or get a pic of my dick, not only would I have said no, I also would have alerted CPS, "They don't have kids yet but you might want to keep an eye on these two!"
And before I went through with something like this, I would need an iron-clad, legally binding agreement, and I would have to actually meet the lawyer who signed off on it, where the husband acknowledged that this was happening with his knowledge, approval and enthusiastic consent. Because if they got divorced and it got messy, he could just say, "The kids aren't mine and I can prove it!" And as the bio-dad, guess who's on the hook for child support?
It also could have been a long game con but for something like that, they would have to count on the person being really naïve and not questioning anything because if that's me, I'm asking for actual proof that they're getting divorced and the husband is claiming that the kids aren't his. Hence why I would ask for a legally-binding document wherein the husband acknowledged that he was aware of what was happening, it was happening with his consent and I was just a sperm donor.