"Male and female He created them" (Genesis 1:27). Rabbi Yitzchak said: When a male comes into the world, peace comes into the world. "Male" [zachar] is like "loaf" [kar], as it is written, "send a lamb [kar]" and so on (Isaiah 16:1); once a male comes, his loaf comes with him. "Male" [zachar] is like "provision" [kar], as it is written (2 Kings 6:23), "and he prepared for them a great provision [kerah]." But a female has nothing with her: a female comes empty [clean of provision], and gets nothing until she asks for her food.
When a Son Is Born Peace and Provision Come Into the World
Yalkut Shimoni on Torah 16:2
זָכָר וּנְקֵבָה בָּרָא אֹתָם, אָמַר רַבִּי יִצְחָק, כֵּיוָן שֶׁבָּא זָכָר לָעוֹלָם בָּא שָׁלוֹם, זָכָר זֶה כַּר דִּכְתִיב "שִׁלְחוּ כַר" וְגוֹ' כֵּיוָן שֶׁבָּא זָכָר בָּא כִּכָּרוֹ עִמּוֹ, זָכָר זֶה כַּר דִּכְתִיב (מלכים ב ו, כג) "וַיִּכְרֶה לָהֶם כֵּרָה" נְקֵבָה אֵין עִמָּהּ כְּלוּם, נְקֵבָה נְקִיָּה בָּאָה, עַד דְּאָמְרָה מְזוֹנֵי לָא יַהֲבֵי לָהּ.