And two completely neurtotypical girls. Both boys with AS have the regressive form.
I was pregnant with DS2 when DS1 developed a latent measles infection an ensuing encephalopathy from his MMR, so that had no impact on our decision to have another just then (though it certainly effected our use of combined MMR subsequently.) DS2 developed autism after being heavy metal poisoned (lead) and then his chelation was severely botched by the hospital, leading to two month stay for sepsis (x2).
Our decision to have a fourth child was based on our future children's needs, not our's as parents. As we were older parents, we knew our eldest DD would someday be responsible for her younger brothers. We decided to give her the gift of a neurologically typical sibling, to support her and help share the load (and joys) of the large responsibility she would carry throughout her life. Knowing that autism is four times as prevalent in boys, we actively "tried" for a girl, and were successful (I think if we were to do it again, I'd go the in-vitro route, to be 100% sure, and to rule out any other defects prior to implantation (I'm not a good candidate for invasive testing such as amnio or CVS due to extreme uterine irritability.))
Our youngest DD is even more NT than her eldest sister. I'm pretty she's going to be President someday.
I don't think we're PollyAnnas, but with lots of intervention and social services supports (and an up-to-date prescription of Wellbutrin for me

), we've tried to make the best of our lot and live life as "normally" as possible. We travel (in fact, just spent six month on the road researching a book on travelling with autistic kids), make sure we have adequate respite for ourselves and our NT kids, and do as much as we can together as a family. We don't allow our NT kids to feel "put upon" or embarrassed of their brothers; if they have friends over, the friends just have to deal with the fact Jonah hates most clothes and Sam wants to join in with nearly everthing his sister does.
For the OP, good luck with your decision. Other than the days we're looking for any passing Gypsy caravan on which to drop her, we thank our lucky stars for our youngest, and never regret our decision. And someday, her big sister will thank us too

.