The Virginia House rejected today a weakened Senate version of a bill to require parental or judicial consent of abortions for girls 17 and younger and embarked on an 11th hour attempt to switch the votes of three senators on the measure.

The 75-to-23 House vote set the stage for sending the bill back to the Senate for consideration. Supporters of the original House bill say that if they can get three senators to switch before the session ends Saturday, the bill will revert to its original form; opponents predict that they will beat back that attempt.

If the Senate insists on its watered-down version, the bill's sponsor, Del. Theodore V. Morrison Jr. (D-Newport News), has said, the bill probably will die.

A Senate committee threw out the bill's requirement for a judge's approval of a minor's abortion and adopted an amendment to require only that sufficient information be obtained from an independent physician for the girl to make a mature and informed decision. The Senate approved the amendments by a vote of 22 to 18 on Friday.

Morrison, who described the Senate version as "an insult" that would make changing the law "nearly meaningless," initially said he was inclined to give up the fight for the stronger language in the face of the Senate opposition.

In a short debate today, Morrison called the Senate version of the bill "a sham" and reiterated arguments that juvenile courts employ trained counselors, and that judges already make difficult and personal decisions in cases such as adoptions. He also said that under the current law, which does not require consent from anyone but the girl for an abortion, some pregnant girls miss out on support from their parents simply because they are afraid to approach them.

Del. Joan H. Munford (D-Montgomery), who opposed Morrison's bill, countered that while legislator-lawyers may know about the counselors in juvenile court, "common everyday lay people do not, particularly young people, who view the courts as a place to go for punishment."

Many legislators say their own views fall in an agonizing space somewhere in between the positions of Morrison and Munford.

In the Senate, William E. Fears (D-Accomack) said he has felt torn on the issue. He said he voted to require parental or judicial consent, partly because of the conservative nature of his constituency. But, he said, "I'm on the fence. I've got mixed emotions. There are a lot of unwanted children."

Antiabortion activists have been vigorously pressing their case with the legislators in the middle ground. "They've been all up and down this hallway, scaring them half to death," said Fears from his third-floor office in the General Assembly building. "They tell them they're not going to vote for them . . . . Frankly, I've been avoiding them."