Fluttershy: “Um, Twilight, I was just curious, and I wanted to ask how you tested this spell? If you don’t mind.”
 
Twilight: “Well, it’s a highly complex process, with a lot of technical terms, but I guess the simplest way to say it is…”
 
Spike: “You two were the first ones she tried it on! How does it feel to make history?”
 
Rainbow Dash: “YOU USED US AS GUINEA PIGS?!”

So that’s how magical lesbian spawn works.

@YetAnotherBrony  
Well, it did say through the “act” of love, so I think the spell needs it, if to activate the magic rather than for biological reasons. Wild passionate horsey lovin’ was had! Lol.
 
Of course, many other things could be considered an act of love… technically.

@YetAnotherBrony
 
Wait, was my comment out-of-bounds for a “Safe” rated image? Argh, wasn’t there an “Edit Comment” button on here a little while ago?

Maybe it’s because I have an incredibly dirty mind, but I like to think that Fluttershy and Rainbow Dash (as well as the other two main couples) still had wild passionate sex that night. The spell probably didn’t even need it to create their child, but they did it anyway, because love! And lust. But mostly love.

…A wizard did it.

@Background Pony #C955  
Hazurasinner’s style is so good. Definitely one of my favourite humanized artists.

@requiem-dirge  
Yes, I meant y. Sorry.

@Background Pony #6694  
Er, you mean “y”. Females have two x chromosomes; males have an x and a y.
 
Also, I love this spell. No gender-bending, just love and magic. :3

@Hugobertington.Esq  
23 chromosomes from each would work fine. If you haven’t noticed, all of these magical lesbian children are female, because there’s no x chromosome.

So… Did Twilight create a spell that turns people into Asari?

…I assume Twi’s spell took into account the necessity of the right chromosomes…. I think

this art style is so cute. Especially fluttershy