royal intermarriage
... that the Habsburgs' frequent practice of royal intermarriage led to severe inbreeding?
... that the <a href="./House_of_Habsburg" id="mwAzw" rel="mw:WikiLink" title="House of Habsburg">Habsburgs</a>' frequent practice of <b id="mwAz0"><a href="./Royal_intermarriage" id="mwAz4" rel="mw:WikiLink" title="Royal intermarriage">royal intermarriage</a></b> led to severe <a href="./Inbreeding" id="mwAz8" rel="mw:WikiLink" title="Inbreeding">inbreeding</a>?