  We prove that if $F$ is a tangent to the identity diffeomorphism at
$0\in\mathbb{C}^2$ and $\Gamma$ is a formal invariant curve of $F$ then there
exists a parabolic curve (attracting or repelling) of $F$ asymptotic to
$\Gamma$. The result is a consequence of a more general one in arbitrary
dimension, where we prove the existence of parabolic curves of a tangent to the
identity diffeomorphism $F$ at $0\in\mathbb{C}^n$ asymptotic to a given formal
invariant curve under some additional conditions, expressed in terms of a
reduction of $F$ to a special normal form by means of blow-ups and
ramifications along the formal curve.
