Love2know, I am not much into karmic astrology, so hopefully someone else can answer your questions about it. A planet in an angular house (#1,4,7, 10) especially when conjunct an angle, is supposed to be strengthened by that position; with the 1st and 10th houses being stronger.
I don't know that it is worthwhile arguing "parents" vs. "fathers"; especially now that some modern astrologers like to blend planets and signs. With the fourth sign Cancer being ruled by the moon, many astrologers today would be just as happy to give Mom the 4th house. The association of the 10th house with the mother comes from the derived or turned house method. The wife of one's father would be the 7th house from the 4th.
However, if the history of astrology is of any interest to people on this thread, I suggest a few cautions. One is that we have to understand how people at past times understood concepts, which may be very different than how we understand them today. For example, today the expression "father of the family" doesn't have nearly the extensive connotations that the term "pater familias" did to the Romans. In a highly patriarchal society (which was the case in the ancient Mediterranean and Near East) one's maternity was of far less consequence than one's paternity. Also, some languages are gendered in ways that English is not. Finally, in a lot of the oldest horoscopes that have come to light (see Neugebauer and Van Hoesen, Greek Horoscopes) houses are scarcely mentioned: just the ascendant and planets in signs. The Babylonians didn't use houses.
JA, how is your Latin or ancient Greek? Where Riley uses the term "parents" in his Vettius translation, do you know what was the word in the original?
This matters, because one might well have a question concerning one's mother that was different than asking about one's father. In Hellenistic astrology these were often determined by "lots" or what were subsequently called Arabian parts that relied upon positions of the planets and ascendant, vs. a particular house.
Some early sources on house meanings are:
O. Neugebauer, 1943, "Demotic Horoscopes", Journal of the American Oriental Society 63: 115-27. This is a fascinating look at 4 horoscope descriptions from archaeological sites, dating to around the turn of the first millenium AD. Neugebauer was a mathematician and historian of science who calculated (by hand in those days!) the planetary positions of many horoscopes of antiquity from both archaeological and literary (like Valens) sources. Demotic was the ancient Egyptian language, writen with Greek characters.
The four horoscopes in this article give the 4th house as "the Dwat" or "the lake of the Dwat." Dwat (Duat, Tuat) was the ancient Egyptian name for the realm of the dead, and it had a firey lake near where the god Osiris and his team judged the dead in Egyptian mythology. However, if we look down the most complete horoscope (dated 18 AD), "the part of the father" is given as Capricorn, which is the same sign given to "the Dwat" or 4th house.
I think Manilius, Astronomica 2 (1st cent. AD) probably had access to now-vanished Egyptian sources, because he does pick up on the underworld and paternal theme for the 4th house. He called houses "temples." He says,
"Where at the opposite pole the universe subsides, occupying the foundations, and from the depths of midnight gloom gazes up at the back of the Earth, in that region Saturn exercises the powers that are his own: cast down himself in ages past...he wields as a father power over the fortunes of fathers and the plight of the old. Daemonium is the name the Greeks have given it..." (2: 929-39I think I can make out the gender in Manilius's "pater in patrios" on the facing page.
Dorotheus (Carmen Astrologium, 1:5, ca. 25-75 AD) simply called the 4th house the "cardine of the earth" or "the cardine under the earth." Cardine apparently means "hinge" and was a name given to the 4 angles. Dorotheus rated the houses in terms of their beneficence, with the 4th house considered good, but rated 7th overall. Dorotheus relied heavily on lots and planetary relations for his delineations, but we do find (in the Pingree translation), that if the sun is in "the cardine under the earth it indicates a fall and a decrease in the property of his fathers, but if the lord of its house or its exaltation overpowers it, it will ameliorate this evil." (2:22.) With some of the other planets in the 4th there is no mention of parents or property but other good/bad things could happen. Jupiter in the 4th bodes well for "parents." It gets a little confusing on the property front because sometimes the 2nd, rather than the 4th house seems intended.
Ptolemy (Tetrabiblos, 2nd century AD) scarcely mentions houses, and does not name the affairs of the 4th house. He relies on relationships between planets for parental information.
Firmicus Maternus (Matheseos Libri VIII, 3rd-4th century AD, 2: 19) calls the 4th house the Imum Caelum ("lowest part of the heavens") and gave it to "family property, substance, possessions, household goods, anything that pertains to hidden and recovered wealth." FM stated that this house was powerful due to its square relationship to the ascendant. In 2:xx, the fourth is the house of "parents."
Firmicus is kind of interesting, because he has a real cookbook of "planets in signs" in book 3. Here we don't find associations of the 4th house with parents as a unit or with Mom, unless the planet is feminine. Saturn in the 4th indicates an early death for the father. Jupiter in the 4th is generally good news for high positions and wealth. The father will be "high born and famous." Mars in the 4th is generally bad news, unless you want to be a soldier. The sun in the 4th signifies "death for the father" and afflictions with any Mars or Saturn aspect to it. Venus in the 4th signifies loss of property. Mercury in the 4th is good for teachers, including of secret arts. FM gives the moon a special treatment depending upon whether she is applying or separating from another planet.
Anyway, since JupiterAsc is our resident expert on Valens (2nd century AD), I encourage JA to carry on with Mr. V's interpretation of the 4th house.