SciFi series with female protagonists, with various degrees of romantic involvement:
Sharon Lee & Steve Miller - Liaden Universe series
Jean Johnson - Theirs Not To Reason Why series
Joel Shepherd - Cassandra Kresnov series
Mike Shepherd - Kris Longknife series
Tanya Huff - Confederation series
David Weber - Honor Harrington series
Debra Doyle & James D. MacDonald - Mageworlds series
Chris Moriarty - Spin series
Ann Aguirre - Sirantha Jax series and Dred Chronicles series
Dana Stabenow - Star Svensdotter series
S L Viehl - Stardoc series
Catherine Asaro - Skolian Empire series and Major Bhaajan series
Rachel Bach - Paradox series
Elizabeth Moon - Vatta's War series
And one with a lot of strong secondary female characters, David Weber & John Ringo - Empire of Man series
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If she's interested in Urban Fantasy, I can provide a list for that, too.
