This is the best, clearest vocations catechism I've seen (which I discovered on the
SSPX vocations page):
It was approved by Cdl. Gibbons.
It is vehemently against mixed marriages, and it unequivocally states that it is
de fide that the state of virginity or celibacy is better and more blessed than that of marriage (cf.
24th session of the Council of Trent on matrimony).