Please answer a question about the following article about Orthodox Judaism:

Orthodox Judaism maintains the historical understanding of Jewish identity. A Jew is someone who was born to a Jewish mother, or who converts to Judaism in accordance with Jewish law and tradition. Orthodoxy thus rejects patrilineal descent as a means of establishing Jewish identity. Similarly, Orthodoxy strongly condemns intermarriage. Intermarriage is seen as a deliberate rejection of Judaism, and an intermarried person is effectively cut off from most of the Orthodox community. However, some Orthodox Jewish organizations do reach out to intermarried Jews.

What does orthodoxy reject as a means of establishing Jewish identiy?
patrilineal descent