Pro_22:6 Train up a child in the way he should go: and when he is old, he will not depart from it.
Can virtue be taught? Absolutely. That's Bible. Children are like sponges; they are going to soak up something. If you - as their parent or teacher - are not teaching them TRUTH and VIRTUE (character) then they are going to soak up the world's truths and the world's image and the result will be ugly. Notice that the above verse does NOT say a child will never stray, only that you will give them a strong foundation that they will return to when they have considered life for themselves. The above is also a general principle, not a 100% blanket statement. Some children will stray and might not return to the path of virtue when they are grown. Parents still are responsible for teaching them.
What is virtue? (Summarized in the above verse as "the way he should go") I will give examples rather than a simple definition.
Gal 5:22 But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith,
Gal 5:23 Meekness, temperance: against such there is no law.
Gal 5:24 And they that are Christ's have crucified the flesh with the affections and lusts.
Pro 31:10 Who can find a virtuous woman? for her price is far above rubies.
Pro 31:11 The heart of her husband doth safely trust in her, so that he shall have no need of spoil.
Pro 31:12 She will do him good and not evil all the days of her life.
Pro 31:13 She seeketh wool, and flax, and worketh willingly with her hands.
Pro 31:14 She is like the merchants' ships; she bringeth her food from afar.
Pro 31:15 She riseth also while it is yet night, and giveth meat to her household, and a portion to her maidens.
Pro 31:16 She considereth a field, and buyeth it: with the fruit of her hands she planteth a vineyard.
Pro 31:17 She girdeth her loins with strength, and strengtheneth her arms.
Pro 31:18 She perceiveth that her merchandise is good: her candle goeth not out by night.
Pro 31:19 She layeth her hands to the spindle, and her hands hold the distaff.
Pro 31:20 She stretcheth out her hand to the poor; yea, she reacheth forth her hands to the needy.
Pro 31:21 She is not afraid of the snow for her household: for all her household are clothed with scarlet.
Pro 31:22 She maketh herself coverings of tapestry; her clothing is silk and purple.
Pro 31:23 Her husband is known in the gates, when he sitteth among the elders of the land.
Pro 31:24 She maketh fine linen, and selleth it; and delivereth girdles unto the merchant.
Pro 31:25 Strength and honour are her clothing; and she shall rejoice in time to come.
Pro 31:26 She openeth her mouth with wisdom; and in her tongue is the law of kindness.
Pro 31:27 She looketh well to the ways of her household, and eateth not the bread of idleness.
Pro 31:28 Her children arise up, and call her blessed; her husband also, and he praiseth her.
Pro 31:29 Many daughters have done virtuously, but thou excellest them all.
Pro 31:30 Favour is deceitful, and beauty is vain: but a woman that feareth the LORD, she shall be praised.
Pro 31:31 Give her of the fruit of her hands; and let her own works praise her in the gates.
What is good citizenship?
Living peaceably as much as possible - Romans 12
Love thy neighbor as thyself
Do justly, love mercy
Be subject to the higher power (governmental authority) insomuch as conscience allows