Permit me to correct you Aishaa:
In Hinduism, there are many many scriptures/stories that recommend this order
1. First and foremost is your Mother,
2. then comes your Father
3. Then comes your Guru
and the fourth comes "God" - or Knowledge of Reality.
And with regards to the main question of this thread, "Do Hindus worship sex symbols?", I have the following thing to say:
IMO, before analyzing a custom or tradition of another sect/culture, it is recommended that we understand the culture very well. For example, a westerner will never be able to appreciate Islamic concept of Purdah, if he/she analyses it from a western perspective. A genuine attempt to understand the Purdah system involves understanding the Islamic culture, social values, and mainly social structure of Islam.
Similarly, you should understand how "Hinduism" treats a the concept of "Sex" before attempting to comprehend the Linga Worship in Hinduism. In Hinduism, the God, the Reality, the Truth is also called as the "Life Force" or "Prana" or "Jeeva". Hindu scriptures explain," the ability/phenomenon that gives the life in me - is the Supreme Reality. What is that in me that makes me to be called as living is actually an effect of that Supreme Truth."
Thus, when life force is attributed as an effect of god, the concept of sexual unision actually takes some spiritual significance, as it is that act that creates life. In Hinduism, sex is not a mere pleasurable act. It is not for fun. It signifies the ability to produce life - where the blessings of "The Reality" is obtained.
Shiva linga - which you refer as the Phallus symbol, signifies the Cosmic Unision of two oppositely charged entities that created the first life in the universe. Worship of Shiva linga is the worship of the Cosmic Reality that we call as "Life".
Any more questions, feel free to shoot!