This article is from the Anne Rice FAQ, by Laura Ann lat13@columbia.edu with numerous contributions by others.
According to what Ash says, a Taltos baby grows more quickly in
the womb when its mother recognizes it for what it is. So, when
a Taltos is pregnant, they obviously know it right away and thus
the baby is born but when a human is pregnant with a Taltos baby,
they don't necessarily know what it is until some time later
(Morrigan, for example, only grew rapidly after Mona knew for sure
that she was pregnant).
 
Continue to: