Now...I dont mean to beat a dead horse or revive a sensitive subject matter. However, I thought these words are very pertinent to our previous discussion on illicit sex.
So here is the paste. In this purport, Prabhupada clearly uses the conjunction "and" and not "or" which means we have to satusfy both conditions for the function to be true. This purport is from SB 3.30.28. This is the entire purport for the text.
Materialistic life is based on sex life. The existence of all the materialistic people, who are undergoing severe tribulation in the struggle for existence, is based on sex. Therefore, in the Vedic civilization sex life is allowed only in a restricted way; it is for the married couple AND ONLY for begetting children. But when sex life is indulged in for sense gratification illegally and illicitly, both the man and the woman await severe punishment in this world or after death. In this world also they are punished by virulent diseases like syphilis and gonorrhea, and in the next life, as we see in this passage of Śrīmad-Bhāgavatam, they are put into different kinds of hellish conditions to suffer. In Bhagavad-gītā, First Chapter, illicit sex life is also very much condemned, and it is said that one who produces children by illicit sex life is sent to hell. It is confirmed here in the Bhāgavatam that such offenders are put into hellish conditions of life in Tāmisra, Andha-tāmisra and Raurava. - SB 3.30.28
So by using the conjunction "AND" and adverb "ONLY"...Prabhupada is clearly and categorically defining the criteria for what is considered licit sex. According to vedic civilisation, this is considered restrictive sex life. Now, if sex within marriage and not for procreation is defined licit (from KC standpoint), then Prabhupada does not have to use the word "only" as a stress as an adverb modifying the verb "beget". From the above sentence, the word beget is functional only for children and within marriage. In my opinion, the word "only" clearly reveals Prabhupada's definition of sex life.
To add, interestingly, after the highlighted sentence, Prabhupada follows with two words "illegal" and "illicit". If we study these two words in context to the previous statement, I intepret the words"illegal" as sex not among married couples and "illicit" as sex not for begetting children. If others have other opinions, please feel free to add.
Many times Prabhupada has either used sex within marriage or begetting children separately as definition for licit sex. This is the first time I am seeing both (marriage and children) in the same sentence. So I thought to paste it here.